Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/015
S. Ishio, F. Aubertin, T. Limbach, H. Engelman, L. Dézsi, U. Gonser, S. M. Fries, M. Takahashi, M. Fujikura
The Mossbauer effect and thermal expansion of rapidly quenched amorphous FexY1-x (0.4
研究了快速淬火非晶态FexY1-x (0.4
{"title":"Mossbauer and magnetovolume effects in amorphous Fe-Y and (Fe-Co) alloys","authors":"S. Ishio, F. Aubertin, T. Limbach, H. Engelman, L. Dézsi, U. Gonser, S. M. Fries, M. Takahashi, M. Fujikura","doi":"10.1088/0305-4608/18/10/015","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/015","url":null,"abstract":"The Mossbauer effect and thermal expansion of rapidly quenched amorphous FexY1-x (0.4<or=x<or=0.8) and (FexCo1-x)0.8Y0.2 (0.4<or=x<or=1.0) alloys were studied to clarify the local environmental effect on the Fe magnetic moments and its contribution to the magnetovolume effect. The Fe atom in the rapidly quenched amorphous Fe-Y alloys has a magnetic moment when it has more than six Fe neighbours. The Fe magnetic moment increases with increasing average number of Fe neighbours n and has a maximum of about 1.9 mu B at n approximately=10-11.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"63 1","pages":"2253-2263"},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83849993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/010
S. Katano, M. Iizumi, Y. Noda
The phonon dispersion relations of ordered and disordered Cu3Au have been measured at room temperature using inelastic neutron scattering techniques. The dispersion curves for the disordered state are very similar to those for pure Cu, while the curves for the ordered state are considerably different from those expected with the assumption that Cu-Au forces are identical to Cu-Cu forces in Cu. Born-von Karman fits to those data are given. The results how that in the ordered state Cu-Au forces are more than five times as strong as Cu-Cu forces. Each force in the disordered state can be regarded as the average of the corresponding forces in the ordered state.
{"title":"Lattice dynamics of Cu3Au in the ordered and disordered states","authors":"S. Katano, M. Iizumi, Y. Noda","doi":"10.1088/0305-4608/18/10/010","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/010","url":null,"abstract":"The phonon dispersion relations of ordered and disordered Cu3Au have been measured at room temperature using inelastic neutron scattering techniques. The dispersion curves for the disordered state are very similar to those for pure Cu, while the curves for the ordered state are considerably different from those expected with the assumption that Cu-Au forces are identical to Cu-Cu forces in Cu. Born-von Karman fits to those data are given. The results how that in the ordered state Cu-Au forces are more than five times as strong as Cu-Cu forces. Each force in the disordered state can be regarded as the average of the corresponding forces in the ordered state.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"43 1","pages":"2195-2202"},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86717941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/002
Zhang Sheng
The temperature (T) dependences of the magnetic susceptibility, chi , electrical resistivity, rho , and elastic modulus, E, of gamma -Fe-31 at.% Mn alloys containing 2.04, 5.33 and 8.71 at.% Si were examined. The Neel transition accompanied by an anomalous change of rho and E has been found in these alloys. With increasing Si content, the Neel temperature TN decreases; for T>TN, the magnetic state of the alloys transforms from Pauli paramagnetism to a paramagnetic state obeying the Curie-Weiss law, and the anomalous resistivity increases rapidly to present a negative temperature coefficient below TN. In lowering the temperature 4.2 K, no second resistivity anomaly for gamma -Fe-31 at.% Mn alloy was found, but a secondary resistivity minimum was observed at about 34 K in the gamma -Fe-31 at.% Mn-5.3 at.% Si alloy. It appears to be due to the Kondo-like effect. This leads the author to assume that both the formation of a localised net magnetic moment on Fe atoms and the transition from incommensurate to commensurate spin-density-wave state are caused by an addition of Si to gamma -Fe-Mn alloys.
{"title":"A study of the Neel transition and the Kondo-like effect of γ-Fe-Mn-Si alloys","authors":"Zhang Sheng","doi":"10.1088/0305-4608/18/10/002","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/002","url":null,"abstract":"The temperature (T) dependences of the magnetic susceptibility, chi , electrical resistivity, rho , and elastic modulus, E, of gamma -Fe-31 at.% Mn alloys containing 2.04, 5.33 and 8.71 at.% Si were examined. The Neel transition accompanied by an anomalous change of rho and E has been found in these alloys. With increasing Si content, the Neel temperature TN decreases; for T>TN, the magnetic state of the alloys transforms from Pauli paramagnetism to a paramagnetic state obeying the Curie-Weiss law, and the anomalous resistivity increases rapidly to present a negative temperature coefficient below TN. In lowering the temperature 4.2 K, no second resistivity anomaly for gamma -Fe-31 at.% Mn alloy was found, but a secondary resistivity minimum was observed at about 34 K in the gamma -Fe-31 at.% Mn-5.3 at.% Si alloy. It appears to be due to the Kondo-like effect. This leads the author to assume that both the formation of a localised net magnetic moment on Fe atoms and the transition from incommensurate to commensurate spin-density-wave state are caused by an addition of Si to gamma -Fe-Mn alloys.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"08 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88512639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/006
L. J. Gallego, J. Somoza, J. Alonso, J. M. López
Predictions of the glass-forming ability and the glass composition range of transition metal alloys are made using a semiempirical theory. The treatment is based on comparing the Gibbs free energies of the competing crystalline and amorphous phases, which requires knowledge of the differences in Gibbs free energy between the amorphous and crystalline phases of the pure elements, Delta Ga-c. In some cases, this quantity can be determined from the available experimental information on glass formation, rather than by using a particular model for Delta Ga-c. The results of the authors' calculations are compared with reported data on systems treated by rapid quenching, mechanical alloying and ion mixing techniques.
{"title":"Prediction of the glass formation range of transition metal alloys","authors":"L. J. Gallego, J. Somoza, J. Alonso, J. M. López","doi":"10.1088/0305-4608/18/10/006","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/006","url":null,"abstract":"Predictions of the glass-forming ability and the glass composition range of transition metal alloys are made using a semiempirical theory. The treatment is based on comparing the Gibbs free energies of the competing crystalline and amorphous phases, which requires knowledge of the differences in Gibbs free energy between the amorphous and crystalline phases of the pure elements, Delta Ga-c. In some cases, this quantity can be determined from the available experimental information on glass formation, rather than by using a particular model for Delta Ga-c. The results of the authors' calculations are compared with reported data on systems treated by rapid quenching, mechanical alloying and ion mixing techniques.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"19 1","pages":"2149-2157"},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80524976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/016
A. H. El-Sayed, G. Nieuwenhuys, J. Mydosh, K. Buschow
The authors have observed the (X-band) electron spin resonance in the equiatomic intermetallic compounds XPtSn, XRhSb and XNiSn, where X=U, Th, Hf, Zr, and Ti. These compounds crystallise in the cubic MgAgAs-type structure and exhibit a semiconducting behaviour in the electrical resistivity at higher temperatures. The ESR lineshapes in bulk samples is of the Dysonian form with an A/B ratio larger than three, which is characteristic of conduction electron spin resonance (CESR). In powdered samples the Dysonian lineshape and the A/B ratio depend on the ratio of sample diameter to the skin depth. The g-values are close to the free-electron value (g=2.0023) except for the U compounds which show both a large g-shift and linewidth. The effective spin density was mostly found to be of the order of 1020 cm-3 at room temperature as measured by comparing the intensity of the ESR signal with that of a known amount of DPPH. The ESR signal of Gd doped into the Hf and U compounds was clearly observed at temperatures where no signal could be found in the pure host materials. Here a negative residual linewidth was found in UPtSn, while the other compounds with Gd obeyed the normal Korringa relation ( Delta H=aT+b) with small thermal broadening and negative g-shift in HfPtSn and positive shift in URhSb.
{"title":"Electron spin resonance in ternary intermetallic compounds with MgAgAs structure","authors":"A. H. El-Sayed, G. Nieuwenhuys, J. Mydosh, K. Buschow","doi":"10.1088/0305-4608/18/10/016","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/016","url":null,"abstract":"The authors have observed the (X-band) electron spin resonance in the equiatomic intermetallic compounds XPtSn, XRhSb and XNiSn, where X=U, Th, Hf, Zr, and Ti. These compounds crystallise in the cubic MgAgAs-type structure and exhibit a semiconducting behaviour in the electrical resistivity at higher temperatures. The ESR lineshapes in bulk samples is of the Dysonian form with an A/B ratio larger than three, which is characteristic of conduction electron spin resonance (CESR). In powdered samples the Dysonian lineshape and the A/B ratio depend on the ratio of sample diameter to the skin depth. The g-values are close to the free-electron value (g=2.0023) except for the U compounds which show both a large g-shift and linewidth. The effective spin density was mostly found to be of the order of 1020 cm-3 at room temperature as measured by comparing the intensity of the ESR signal with that of a known amount of DPPH. The ESR signal of Gd doped into the Hf and U compounds was clearly observed at temperatures where no signal could be found in the pure host materials. Here a negative residual linewidth was found in UPtSn, while the other compounds with Gd obeyed the normal Korringa relation ( Delta H=aT+b) with small thermal broadening and negative g-shift in HfPtSn and positive shift in URhSb.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"1 1","pages":"2265-2281"},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72549587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/012
P. Son, H. Kempen, P. Wyder
Electrons that are injected into a Ag single-crystal slab at a point contact are focused back onto the contact as holes after Andreev reflection at a Ag-Pb interface. A small applied magnetic field shifts the position of the focusing spot on the scale of the point-contact diameter. The excess current due to the holes is measured both as a function of magnetic field and as a functions of voltage. The results do not completely agree with a simple ballistic model. The deviation for large magnetic field can be understood qualitatively by assuming that the electrons and holes are deflected at random over small angles, for instance by the long-range strain field of dislocations. The observed structure of the excess current for small magnetic field and voltage is probably related to the presence of scattering centres in the point-contact area, although not all features can be explained this way. The corresponding length scales imply that the wave character of the quasi-particles has to be taken into account.
{"title":"Excess current of a point contact on a normal-metal single crystal backed by a superconductor","authors":"P. Son, H. Kempen, P. Wyder","doi":"10.1088/0305-4608/18/10/012","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/012","url":null,"abstract":"Electrons that are injected into a Ag single-crystal slab at a point contact are focused back onto the contact as holes after Andreev reflection at a Ag-Pb interface. A small applied magnetic field shifts the position of the focusing spot on the scale of the point-contact diameter. The excess current due to the holes is measured both as a function of magnetic field and as a functions of voltage. The results do not completely agree with a simple ballistic model. The deviation for large magnetic field can be understood qualitatively by assuming that the electrons and holes are deflected at random over small angles, for instance by the long-range strain field of dislocations. The observed structure of the excess current for small magnetic field and voltage is probably related to the presence of scattering centres in the point-contact area, although not all features can be explained this way. The corresponding length scales imply that the wave character of the quasi-particles has to be taken into account.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"700 1","pages":"2211-2221"},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76890740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/004
P. Steiner, B. Siegwart, I. Sander, A. Kolodziejczyk, K. Krop
ESCA experiment of the relevant core levels and valence bands of Y9Co7 and pure Y and Co have been performed with monochromatised Al Ka radiation. The magnetisation, AC susceptibility and resistivity were also measured as functions of temperature. Some conclusions were drawn about stronger localisation of the d electrons in Y9Co7 than in metallic Co and an enhanced density of d states at the Fermi level in Y9Co7.
{"title":"ESCA investigations of a magnetic superconductor Y9Co7","authors":"P. Steiner, B. Siegwart, I. Sander, A. Kolodziejczyk, K. Krop","doi":"10.1088/0305-4608/18/10/004","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/004","url":null,"abstract":"ESCA experiment of the relevant core levels and valence bands of Y9Co7 and pure Y and Co have been performed with monochromatised Al Ka radiation. The magnetisation, AC susceptibility and resistivity were also measured as functions of temperature. Some conclusions were drawn about stronger localisation of the d electrons in Y9Co7 than in metallic Co and an enhanced density of d states at the Fermi level in Y9Co7.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"123 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77613191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/011
T. Endo, T. Kino
The logarithmic temperature dependence of the dislocation resistivity rho d(T) found by Endo et al (1985) is investigated experimentally in more detail for samples of different deformation modes from those used in the previous experiment. The behaviour of the logarithmic temperature dependence is found to be very sensitive to the dislocation density and its configuration, and also to the species of solute atoms and their concentrations. The results are analysed using the expression rho d(T)=A-B log(T2+TDelta 2) previously introduced, where A and B are constants and TDelta is a characteristic temperature. An experimental relation between TDelta and B is found to coincide with the one proposed by Cochrane et al (1975) and Tsuei (1978) on the basis of the two-level system.
Endo等人(1985)发现的位错电阻率rho d(T)的对数温度依赖关系，在实验中更详细地研究了与先前实验中使用的不同变形模式的样品。发现对数温度依赖的行为对位错密度及其构型非常敏感，对溶质原子的种类及其浓度也非常敏感。结果使用表达式rho d(T)=A-B log(T2+TDelta 2)进行分析，其中A和B是常数，TDelta是特征温度。实验发现，TDelta与B之间的关系与Cochrane et al(1975)和Tsuei(1978)基于两级系统提出的关系一致。
{"title":"Logarithmic temperature dependence of the electrical resistivity due to dislocation in metals","authors":"T. Endo, T. Kino","doi":"10.1088/0305-4608/18/10/011","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/011","url":null,"abstract":"The logarithmic temperature dependence of the dislocation resistivity rho d(T) found by Endo et al (1985) is investigated experimentally in more detail for samples of different deformation modes from those used in the previous experiment. The behaviour of the logarithmic temperature dependence is found to be very sensitive to the dislocation density and its configuration, and also to the species of solute atoms and their concentrations. The results are analysed using the expression rho d(T)=A-B log(T2+TDelta 2) previously introduced, where A and B are constants and TDelta is a characteristic temperature. An experimental relation between TDelta and B is found to coincide with the one proposed by Cochrane et al (1975) and Tsuei (1978) on the basis of the two-level system.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"5 1","pages":"2203-2210"},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82155358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/007
Ajay Gupta, M. Jayaraj, S. Lal, R. P. Verma
The crystallisation behaviour of a-Fe78Si9B11C2 has been studied using differential scanning calorimetry, Mossbauer spectroscopy and length change measurement. The isothermal kinetics of crystallisation are followed by measuring the change in length of the specimen. Data have been analysed in terms of a theoretical model which takes into account the effect of crystal growth on pre-existing nuclei. Quenched-in nuclei are found to affect the kinetics of crystallisation significantly. A detailed analysis of the data yields activation energies for both nucleation and growth of crystallites, information that is normally obtainable only through TEM.
{"title":"Effect of quenched-in nuclei on the crystallisation kinetics of metallic glasses","authors":"Ajay Gupta, M. Jayaraj, S. Lal, R. P. Verma","doi":"10.1088/0305-4608/18/10/007","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/007","url":null,"abstract":"The crystallisation behaviour of a-Fe78Si9B11C2 has been studied using differential scanning calorimetry, Mossbauer spectroscopy and length change measurement. The isothermal kinetics of crystallisation are followed by measuring the change in length of the specimen. Data have been analysed in terms of a theoretical model which takes into account the effect of crystal growth on pre-existing nuclei. Quenched-in nuclei are found to affect the kinetics of crystallisation significantly. A detailed analysis of the data yields activation energies for both nucleation and growth of crystallites, information that is normally obtainable only through TEM.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"31 1","pages":"2159-2160"},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87369777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-10-01DOI: 10.1088/0305-4608/18/10/008
A. Mookerjee, R. Singh
The augmented space cluster coherent potential approximation is applied to the study of the vibrational properties of NiPd and NiCr alloys. Together with the earlier work on NiPt, this forms a systematic study of effects of large mass and force-constant disorders and clustering effects. The AS-CCPA represents a significant improvement over the earlier MCPA calculations in comparison with experimental data.
{"title":"Vibrational properties of NiPd and NiCr alloys","authors":"A. Mookerjee, R. Singh","doi":"10.1088/0305-4608/18/10/008","DOIUrl":"https://doi.org/10.1088/0305-4608/18/10/008","url":null,"abstract":"The augmented space cluster coherent potential approximation is applied to the study of the vibrational properties of NiPd and NiCr alloys. Together with the earlier work on NiPt, this forms a systematic study of effects of large mass and force-constant disorders and clustering effects. The AS-CCPA represents a significant improvement over the earlier MCPA calculations in comparison with experimental data.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"81 1","pages":"2171-2180"},"PeriodicalIF":0.0,"publicationDate":"1988-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75907502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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