2020/10/14 by Ajay Kumar, Björn Schwarz, B. Schwarz +3
Chemistry · Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Chemistry #Condensed matter physics #Electronic and Structural Properties of Oxides #Energy (signal processing) #Magnetic and transport properties of perovskites and related materials #Magnetic susceptibility #Paramagnetism #Physics #Quantum mechanics #Relaxation (psychology) #Spin (aerodynamics) #Spin glass #Thermodynamics #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.102.184414
published as Physical Review B, 102, 184414 (2020 · accepted for publication in PRB
arxiv created 2020/10/14 · openalex created_date 2020/10/22 · openalex publication_date 2020/11/12 · arxiv updated 2020/11/30 · openalex updated_date 2026/08/05
We report the detailed analysis of specific heat [CP(T)] and ac susceptibility for magnetically frustrated Sr_2\ensuremath-xLaxCoNbO6 (x=0--1) double perovskites to understand low-temperature complex magnetic interactions and their evolution with x. Interestingly, the observed Schottky anomaly in the x\ensuremath\leqslant0.4 samples shifts gradually toward higher temperatures with magnetic field as well as x, and the analysis reveals the persistence of the discrete energy states in these samples resulting from the spin-orbit coupling and octahedral distortion. Moreover, the extracted values of the Land'e g factor indicate the existence of high-spin state Co3+ ions energetically close to a nonmagnetic low-spin state. The specific-heat data show the \ensuremathλ-type anomaly for the x\ensuremath\geqslant0.6 samples due to evolution of the long-range antiferromagnetic ordering. Our analysis of low-temperature CP(T) data for the x\ensuremath\geqslant0.6 samples demonstrates the 3D isotropic Heisenberg antiferromagnetic (AFM) interactions and the temperature-induced second-order AFM-paramagnetic phase transition. More interestingly, we demonstrate the presence of the free Co2+-like Kramers doublet ground state in the x=1 sample. Further, the ac susceptibility and time evolution of the magnetization data reveal the low-temperature cluster-glass-like behavior in the x=0--0.4 samples, where spin-spin correlation strength decreases with x.