Magnetic, magnetocaloric and critical behavior investigation of Nd0.7Ca0.15Sr0.15MnO3 prepared by high-energy ball milling

Abstract Magnetic, magnetocaloric and critical behavior properties of Nd 0.7 Ca 0.15 Sr 0.15 MnO 3 polycrystalline prepared by high-energy ball milling are studied. The current study is a comparison between two different ball-milling times (4 h milling and 24 h, NCSMO1 and NCSMO2, respectively). Phase purity and structure are investigated using X-ray diffraction (XRD). The Rietveld refinements of the X-ray diffraction patterns show that our samples crystallize in the orthorhombic structure with ‘ Pnma ’ space group. Both compounds NCSMO1 and NCSMO2, exhibit a clear ferromagnetic (FM)-paramagnetic (PM) transition. The Curie temperature (T C ) increased slightly with increasing milling time from 123 K to 127 K, for NCSMO1 and NCSMO2 respectively. Moreover, the magnetic entropy change ( − Δ S M ) and the relative cooling power (RCP) decreased slightly with increasing milling time. A detailed critical behavior study around T C has been conducted. The critical exponents β, γ and δ have been determined using various techniques such as the modified Arrott plot (MAP), the Kouvel-Fisher methods (KF) as well as the critical isotherm (CI). The values of critical exponents are close to the Tricritical mean-field and the 3d-Ising models for NCSMO1 and NCSMO2, respectively. On the basis of these critical exponents, the magnetization, field and temperature data (M-H-T) around T C collapse onto two curves (one for T C and another for T>T C ) obeying the single scaling equation M ( μ 0 H , e ) = ( e ) β f ± ( μ 0 H / e β + γ ) , thus confirming that the obtained values of β, γ and δ are reasonably accurate and unambiguous.