Sharma Mohit K, Yadav Kavita, Mukherjee K
School of Basic Sciences, Indian Institute of Technology, Mandi, Himachal Pradesh 175005, India.
J Phys Condens Matter. 2018 May 31;30(21):215803. doi: 10.1088/1361-648X/aabbfe. Epub 2018 Apr 5.
The binary intermetallic compound ErPd has been investigated using dc and ac magnetic susceptibilities, magnetic memory effect, isothermal magnetization, non-linear dc susceptibility, heat capacity and magnetocaloric effect studies. Interestingly, even though the compound does not show geometrical frustration it undergoes glassy magnetic phase transition below 17.2 K. Investigation of dc magnetization and heat capacity data divulged absence of long-ranged magnetic ordering. Through the magnetic memory effect, time dependent magnetization and ac susceptibility studies it was revealed that the compound undergoes glass-like freezing below 17.2 K. Analysis of frequency dependence of this transition temperature through scaling and Arrhenius law; along with the Mydosh parameter indicate, that the dynamics in ErPd are due to the presence of strongly interacting superspins rather than individual spins. This phase transition was further investigated by non-linear dc susceptibility and was characterized by static critical exponents γ and δ. Our results indicate that this compound shows the signature of superspin glass at low temperature. Additionally, both conventional and inverse magnetocaloric effect was observed with a large value of magnetic entropy change and relative cooling power. Our results suggest that ErPd can be classified as a superspin glass system with large magnetocaloric effect.
已通过直流和交流磁化率、磁记忆效应、等温磁化、非线性直流磁化率、热容量和磁热效应研究对二元金属间化合物ErPd进行了研究。有趣的是，尽管该化合物未表现出几何阻挫，但它在17.2 K以下经历了玻璃态磁相变。对直流磁化和热容量数据的研究表明不存在长程磁有序。通过磁记忆效应、随时间变化的磁化和交流磁化率研究发现，该化合物在17.2 K以下经历了类玻璃态冻结。通过标度和阿仑尼乌斯定律对该转变温度的频率依赖性进行分析；连同米多什参数表明，ErPd中的动力学是由于存在强相互作用的超自旋而非单个自旋。通过非线性直流磁化率对该相变进行了进一步研究，并由静态临界指数γ和δ进行了表征。我们的结果表明，该化合物在低温下表现出超自旋玻璃的特征。此外，还观察到了传统和逆磁热效应，其磁熵变和相对冷却功率值都很大。我们的结果表明，ErPd可归类为具有大磁热效应的超自旋玻璃系统。
