Evolution of Magnetism Induced by K+/La3+ Implantations in Double Perovskite Ba2MnTeO6

B-site rock salt type ordered double perovskites with general formula A₂B′B″X₆ have attracted a variety of attention due to remarkable magnetic properties and potential applications in spintronics. Here we report the structural, magnetic, and electronic properties of polycrystalline compounds Ba₂MnTeO₆ and (Ba_0.9X_0.1)₂MnTeO₆ (X = K/La) by powder X-ray diffraction, magnetic susceptibility measurements, specific heat measurements, and X-ray photoelectron spectroscopy. Ba₂MnTeO₆ is antiferromagnetically ordered below 20 K. Density functional theory calculations show that Ba₂MnTeO₆ prefers type III antiferromagnetic order with a dominant antiferromagnetic nearest-neighbor exchange and a weak ferromagnetic next-nearest-neighbor exchange. Our Monte Carlo simulations lead to a transition temperature of 28 K, consistent with the experimental results. Upon K⁺/La³⁺ cations’ implantation on Ba sites, while (Ba_0.9K_0.1)₂MnTeO₆ orders antiferromagnetically at 20 K, (Ba_0.9La_0.1)₂MnTeO₆ exhibits superparamagnetism below room temperature, which may originate from oxygen ion adsorptions. These findings reveal the modulation of magnetism for Ba₂MnTeO₆, which may hint at potential applications of double perovskites in magnetic devices.