Magnetic structure and magneto-elastic-structural coupling in Cr-modified SrRuO₃: A neutron powder diffraction study

Abstract

Temperature dependent neutron powder diffraction and magnetization studies have been carried out on a Cr-substituted SrRuO₃ close to the solubility limit, that is, SrRu_0.88Cr_0.12O₃ (SRC-12). Evidence of ferromagnetic ordering below 200 K was deduced from magnetization studies as well as from neutron powder diffraction. The magnetic lattice coincides with the chemical one (k = 0) and the major component of the ordered magnetic moment has been found along the c-axis. The system exhibits anomalous variation in the cell volume close to the magnetic ordering temperature. The spontaneous magnetostrictive strain below the ordering temperature, estimated by fitting the temperature dependence of the lattice parameters and the cell volume using Debye–Grüneisen function, revealed that the main contribution to the volume magnetostriction comes from the c-axis. The magneto-elastic behavior is further shown to be coupled to the octahedral tilt about the c axis. The analysis of magnetic structure and the magneto-elastic strain suggests c axis to be the easy axis of magnetization for this system.