Second-order magnetic phase transition in orthorhombic Pr0.7Ca0.15Ba0.15MnO3

作者：The Long Phan; Zhang P; Thanh T D; Tran Q T; Yu S C^*

来源：Solid State Communications, 2014, 191: 25-29.

DOI：10.1016/j.ssc.2014.04.009

• Perovskite manganites
• Magnetic properties
• Critical behavior

We have studied the critical behavior around the ferromagnetic-paramagnetic (FM-PM) phase transition (the Curie temperature, T-C) of a polycrystalline manganite Pr0.7Ca0.15Ba0.15MnO3. The assessments based on Banejee%26apos;s criteria reveals the sample undergoing a second-order magnetic phase transition. The use of the modified Arrott and Kouvel-Fisher methods determined the values of critical parameters T-C approximate to 117 K, beta=0.403 +/- 0.024 and gamma=1.242 +/- 0.033. With these values, magnetic-field dependences of magnetization at temperatures around T-C (M-H-T curves) can be well described by the universal function of M(H, epsilon) = vertical bar epsilon vertical bar(beta)f (+/-) (H/vertical bar epsilon vertical bar(beta+gamma)), where epsilon=(T-T-C)/T-C, and f(+) and f(-) are regular functions for T %26gt; T-C and T %26lt; T-C respectively. Compared with the theoretical models, the beta value obtained in our work is located in between those expected for the mean-field theory and the 3D Heisenberg model, while the gamma value is close to that expected for the 3D Ising model. Such results demonstrate the coexistence of short- and long-range FM orders in Pr0.7Ca0.15Ba0.15MnO3. This is ascribed to magnetic inhomogeneity caused by Ba2+- and Ca2+-rich regions, and the coexistence of FM and anti-FM interactions.

• 出版日期2014-8