Pub Date : 1988-11-01DOI: 10.1088/0305-4608/18/11/020
J. Inoue, M. Shimizu
The types of magnetic phase transitions (first- or second-order) in (R-Y)Co2 and RCo2 (R=heavy rare-earth element) under high pressure are studied by making use of a phenomenological model where the coexistence of localised moments on R atoms and itinerant d electrons is assumed. The concentration dependence of the Curie temperature TC of R(Co-Al)2 is calculated in the same model. The calculated results of the boundary between the first- and second-order transitions are consistent with the observed results for (Er-Y)Co2 and (Ho-Y)Co2. The calculated values of TC for R(Co-Al)2 agree well with the experimental ones.
{"title":"First- and second-order magnetic phase transitions in (R-Y)Co2 and R(Co-Al)2 (R=heavy rare-earth element) compounds","authors":"J. Inoue, M. Shimizu","doi":"10.1088/0305-4608/18/11/020","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/020","url":null,"abstract":"The types of magnetic phase transitions (first- or second-order) in (R-Y)Co2 and RCo2 (R=heavy rare-earth element) under high pressure are studied by making use of a phenomenological model where the coexistence of localised moments on R atoms and itinerant d electrons is assumed. The concentration dependence of the Curie temperature TC of R(Co-Al)2 is calculated in the same model. The calculated results of the boundary between the first- and second-order transitions are consistent with the observed results for (Er-Y)Co2 and (Ho-Y)Co2. The calculated values of TC for R(Co-Al)2 agree well with the experimental ones.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"16 1","pages":"2487-2497"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86006005","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 : 1988-11-01DOI: 10.1088/0305-4608/18/11/011
Yu.I. Vesnin, Y. Shubin
Sub-eutectic solid solubilities in the silver-copper system have been determined using high-temperature X-ray diffractometry and applying Vegard's rule. The temperature at which solid solubility first becomes perceptible is found to be Tv approximately=380 degrees C by X-ray analysis. Thermoelectric measurements on the Ag-Cu couple showed no sharp changes in TEMF with temperature, but gave a minimum also at 380 degrees C.
{"title":"Equilibrium solid solubilities in the Ag-Cu system by X-ray diffractometry","authors":"Yu.I. Vesnin, Y. Shubin","doi":"10.1088/0305-4608/18/11/011","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/011","url":null,"abstract":"Sub-eutectic solid solubilities in the silver-copper system have been determined using high-temperature X-ray diffractometry and applying Vegard's rule. The temperature at which solid solubility first becomes perceptible is found to be Tv approximately=380 degrees C by X-ray analysis. Thermoelectric measurements on the Ag-Cu couple showed no sharp changes in TEMF with temperature, but gave a minimum also at 380 degrees C.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"6 1","pages":"2381-2386"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85881241","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 : 1988-11-01DOI: 10.1088/0305-4608/18/11/001
H. Starnberg, P. Nilsson
The self-energy responsible for the narrowing of the Ni 3d band as observed in photoemission data is obtained from a comparison of a calculated band structure with a band structure determined from photoemission data. The self-energy is found to depend on both wavevector k and band index n, but the authors are able to demonstrate that this dependence is almost exclusively introduced through the hybridisation with sp bands. The self-energy of pure d states is found to be linear, Sigma ( epsilon )=-0.44 epsilon , down to about 3 eV below the Fermi energy.
{"title":"Experimental self-energy corrections to the Ni valence band","authors":"H. Starnberg, P. Nilsson","doi":"10.1088/0305-4608/18/11/001","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/001","url":null,"abstract":"The self-energy responsible for the narrowing of the Ni 3d band as observed in photoemission data is obtained from a comparison of a calculated band structure with a band structure determined from photoemission data. The self-energy is found to depend on both wavevector k and band index n, but the authors are able to demonstrate that this dependence is almost exclusively introduced through the hybridisation with sp bands. The self-energy of pure d states is found to be linear, Sigma ( epsilon )=-0.44 epsilon , down to about 3 eV below the Fermi energy.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85047231","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 : 1988-11-01DOI: 10.1088/0305-4608/18/11/015
R. Stubi, P. Probst, R. Huguenin, V. Gasparov
The electron-phonon scattering rates vep(T) of electrons on extremal belly orbits perpendicular to the (111) and (100) directions have been measured between 0.5 and 8 K in Cu and Ag. Departures from the usual T3 regime are attributed to the changing effectiveness of the electron scattering with temperature and to the energy dependence of the electron-phonon scattering rate. Simple models including these effects describe the experimental data very well over the whole temperature interval and explain discrepancies between previous measurements performed on samples of different thickness. The results are consistent with data from transverse electron focusing and surface Landau level experiments.
{"title":"Electron-phonon scattering in copper and silver from radio-frequency size effect measurements","authors":"R. Stubi, P. Probst, R. Huguenin, V. Gasparov","doi":"10.1088/0305-4608/18/11/015","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/015","url":null,"abstract":"The electron-phonon scattering rates vep(T) of electrons on extremal belly orbits perpendicular to the (111) and (100) directions have been measured between 0.5 and 8 K in Cu and Ag. Departures from the usual T3 regime are attributed to the changing effectiveness of the electron scattering with temperature and to the energy dependence of the electron-phonon scattering rate. Simple models including these effects describe the experimental data very well over the whole temperature interval and explain discrepancies between previous measurements performed on samples of different thickness. The results are consistent with data from transverse electron focusing and surface Landau level experiments.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"12 1","pages":"2429-2443"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78416752","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 : 1988-11-01DOI: 10.1088/0305-4608/18/11/008
D. González, M. Silbert
The authors present the results of numerical calculations, in the mean spherical approximation (MSA), for model liquid binary alloys interacting via Yukawa potentials, namely phi ij(r)=Aijexp(- lambda r)/r. They have chosen parameters which allow the description of the structural properties of liquids Li-Na and Li-Pb at different concentrations and Li4Pb at three temperatures. They show: (i) that once the ordering potential, nu (r)=1/2( phi 11(r)+ phi 22(r)-2 phi 12(r)), is specified the total structure factor S(k), the concentration-concentration partial structure factor Scc(k) and the number-number partial structure factor SNN(k) are insensitive to changes in the pair interactions phi ij(r); and (ii) that the thermodynamic properties-specifically Scc(0) and the correlation energy-are sensitive to changes in phi ij(r).
{"title":"Ordering potential and the structural properties of binary Yukawa mixtures","authors":"D. González, M. Silbert","doi":"10.1088/0305-4608/18/11/008","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/008","url":null,"abstract":"The authors present the results of numerical calculations, in the mean spherical approximation (MSA), for model liquid binary alloys interacting via Yukawa potentials, namely phi ij(r)=Aijexp(- lambda r)/r. They have chosen parameters which allow the description of the structural properties of liquids Li-Na and Li-Pb at different concentrations and Li4Pb at three temperatures. They show: (i) that once the ordering potential, nu (r)=1/2( phi 11(r)+ phi 22(r)-2 phi 12(r)), is specified the total structure factor S(k), the concentration-concentration partial structure factor Scc(k) and the number-number partial structure factor SNN(k) are insensitive to changes in the pair interactions phi ij(r); and (ii) that the thermodynamic properties-specifically Scc(0) and the correlation energy-are sensitive to changes in phi ij(r).","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"60 1","pages":"2353-2362"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79339436","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 : 1988-11-01DOI: 10.1088/0305-4608/18/11/012
W. Temmerman, P. Durham, Z. Szotek, M. Šob, C. G. Larsson
The authors present first-principles one-electron calculations of angle-resolved photoemission spectra and electron-positron momentum densities in equiatomic Cu-Zn alloys ( beta brass). Many-body and instrumental effects are included by realistic phenomenological procedures. They predict that the changes in electronic structure across the order-disorder transformation should be clearly reflected in photoemission, and somewhat less pronounced in positron annihilation. They demonstrate, however, that the two techniques are complementary, and that combined studies should be a powerful probe of ordering phenomena at the electronic level.
{"title":"Electronic effects in the order-disorder transition in β brass","authors":"W. Temmerman, P. Durham, Z. Szotek, M. Šob, C. G. Larsson","doi":"10.1088/0305-4608/18/11/012","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/012","url":null,"abstract":"The authors present first-principles one-electron calculations of angle-resolved photoemission spectra and electron-positron momentum densities in equiatomic Cu-Zn alloys ( beta brass). Many-body and instrumental effects are included by realistic phenomenological procedures. They predict that the changes in electronic structure across the order-disorder transformation should be clearly reflected in photoemission, and somewhat less pronounced in positron annihilation. They demonstrate, however, that the two techniques are complementary, and that combined studies should be a powerful probe of ordering phenomena at the electronic level.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"19 1","pages":"2387-2408"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80658851","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 : 1988-11-01DOI: 10.1088/0305-4608/18/11/003
S. Takahashi, Y. Umakoshi
Magnetic susceptibility was measured in a plastically deformed 25.6 at.% Fe-Pt single crystal. The susceptibility decreases considerably for 1.3% strain and at the same time spontaneous magnetisation appears. On cooling, the spontaneous magnetisation increases rapidly near the Neel temperatures. Fe atoms at the irregular sites induced by plastic deformation exert a destructive influence on magnetic ordering at distances as great as 103 AA. They enhance the magnetic exchange interaction of neighbouring Fe atoms at the regular sites and change them to ferromagnetic near the Neel temperatures.
{"title":"The influence of plastic deformation on the antiferromagnetic ordering in a chemically ordered FePt3 alloy","authors":"S. Takahashi, Y. Umakoshi","doi":"10.1088/0305-4608/18/11/003","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/003","url":null,"abstract":"Magnetic susceptibility was measured in a plastically deformed 25.6 at.% Fe-Pt single crystal. The susceptibility decreases considerably for 1.3% strain and at the same time spontaneous magnetisation appears. On cooling, the spontaneous magnetisation increases rapidly near the Neel temperatures. Fe atoms at the irregular sites induced by plastic deformation exert a destructive influence on magnetic ordering at distances as great as 103 AA. They enhance the magnetic exchange interaction of neighbouring Fe atoms at the regular sites and change them to ferromagnetic near the Neel temperatures.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"185 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77103399","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 : 1988-11-01DOI: 10.1088/0305-4608/18/11/007
P. Salmon
The static structure factor S(k) and pair distribution function g(r) of liquid germanium at 1000 degrees C were measured using neutron diffraction. A wider k-range was covered that in previous diffraction experiments on liquid Ge and particular attention was given to the data analysis procedure used to extra S(k) from the measured intensities. The g(r) has a first peak at 2.66+or-0.02 AA and gives an averaged coordination number of 5.6. The results are discussed with reference to the previous diffraction studies on liquid Ge and systematic differences between the neutron and X-ray results are observed.
{"title":"A neutron diffraction study on the structure of liquid germanium","authors":"P. Salmon","doi":"10.1088/0305-4608/18/11/007","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/007","url":null,"abstract":"The static structure factor S(k) and pair distribution function g(r) of liquid germanium at 1000 degrees C were measured using neutron diffraction. A wider k-range was covered that in previous diffraction experiments on liquid Ge and particular attention was given to the data analysis procedure used to extra S(k) from the measured intensities. The g(r) has a first peak at 2.66+or-0.02 AA and gives an averaged coordination number of 5.6. The results are discussed with reference to the previous diffraction studies on liquid Ge and systematic differences between the neutron and X-ray results are observed.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"47 1","pages":"2345-2352"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84547607","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 : 1988-11-01DOI: 10.1088/0305-4608/18/11/018
C. Elsässer, M. Fähnle, E. Brandt, M. Böhm
The local magnetic anisotropy in amorphous transition metal alloys caused by local spin-orbit coupling has been studied by a perturbation treatment on the basis of a semi-empirical self-consistent Hartree-Fock approach for 55 different amorphous iron clusters (12-14 atoms). The corresponding structural units have been selected from a large amorphous model structure (2048 atoms). The numerical approach leads to a random distribution of the local easy directions and local anisotropy energies. The latter are of the same order of magnitude as those of uniaxial crystalline ferromagnets. The present theory is compared with the point-charge model of Cochrane et al. (1974), for the local anisotropy in amorphous alloys containing rare-earth atoms.
在半经验自一致Hartree-Fock方法的基础上，对55种不同的非晶态铁簇(12-14个原子)进行了微扰处理，研究了非晶态过渡金属合金中局部自旋-轨道耦合引起的局部磁各向异性。相应的结构单元已从一个大型非晶模型结构(2048个原子)中选择。数值方法导致了局部易方向和局部各向异性能量的随机分布。后者与单轴晶体铁磁体具有相同的数量级。本理论与Cochrane et al.(1974)的点电荷模型进行了比较，研究了含稀土原子的非晶合金的局部各向异性。
{"title":"Theory of local magnetic anisotropy in amorphous alloys","authors":"C. Elsässer, M. Fähnle, E. Brandt, M. Böhm","doi":"10.1088/0305-4608/18/11/018","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/018","url":null,"abstract":"The local magnetic anisotropy in amorphous transition metal alloys caused by local spin-orbit coupling has been studied by a perturbation treatment on the basis of a semi-empirical self-consistent Hartree-Fock approach for 55 different amorphous iron clusters (12-14 atoms). The corresponding structural units have been selected from a large amorphous model structure (2048 atoms). The numerical approach leads to a random distribution of the local easy directions and local anisotropy energies. The latter are of the same order of magnitude as those of uniaxial crystalline ferromagnets. The present theory is compared with the point-charge model of Cochrane et al. (1974), for the local anisotropy in amorphous alloys containing rare-earth atoms.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"28 1","pages":"2463-2477"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84615527","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 : 1988-11-01DOI: 10.1088/0305-4608/18/11/016
D. Shaltiel, M. Reshotko, A. Grayevsky, J. Burger, J. Daou, P. Vajda
The electrical resistivity of TiBe2 shows anomalous behaviour at high temperature characterised by a strong reduction of the slope (d rho /dT); the authors interpret this in terms of a decoupling of the s- (or p-) like and d-like states and show that the corresponding s-d scattering resistivity rho sd tends to saturate above 300 K. The conduction electron spin resonance linewidth, which is due mainly to electron-lattice relaxation, is expected to vary like the resistivity and indeed they observe a sharp saturation of it above approximately=200 K indicating that it is more likely related to rho sd(or rho dd) rather than to the global resistivity; the saturation becomes less sharp if the residual resistivity increases, indicating a strong coupling, probably of the s-like electrons with the lattice via the local defects.
{"title":"Saturation with temperature of the electrical resistivity and the CESR linewidth in TiBe2","authors":"D. Shaltiel, M. Reshotko, A. Grayevsky, J. Burger, J. Daou, P. Vajda","doi":"10.1088/0305-4608/18/11/016","DOIUrl":"https://doi.org/10.1088/0305-4608/18/11/016","url":null,"abstract":"The electrical resistivity of TiBe2 shows anomalous behaviour at high temperature characterised by a strong reduction of the slope (d rho /dT); the authors interpret this in terms of a decoupling of the s- (or p-) like and d-like states and show that the corresponding s-d scattering resistivity rho sd tends to saturate above 300 K. The conduction electron spin resonance linewidth, which is due mainly to electron-lattice relaxation, is expected to vary like the resistivity and indeed they observe a sharp saturation of it above approximately=200 K indicating that it is more likely related to rho sd(or rho dd) rather than to the global resistivity; the saturation becomes less sharp if the residual resistivity increases, indicating a strong coupling, probably of the s-like electrons with the lattice via the local defects.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"32 1","pages":"2445-2450"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73605216","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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