Magnetic phase transitions in SmCoAsO

TL;DR

This study investigates the magnetic phase transitions in SmCoAsO, revealing three distinct magnetic states and the effects of Fe substitution, using magnetization, x-ray diffraction, and specific-heat measurements.

Contribution

It provides detailed characterization of magnetic transitions in SmCoAsO and assesses the impact of Fe doping on its magnetic properties.

Findings

Identified three magnetic phase transitions at 57 K, 45 K, and 5 K.

Confirmed the itinerant ferromagnetic nature of Co sublattice.

Fe substitution was ineffective in altering magnetic behavior.

Abstract

Magnetization, x-ray diffraction and specific-heat measurements reveal that SmCoAsO undergoes three magnetic phase transitions. A ferromagnetic transition attributed to the Co ions, emerges at TC=57 K with a small saturation moment of 0.15muB/Co. Reorientation of the Co moment to an antiferromagnetic state is obtained at TN2=45 K. The relative high paramagnetic effective moment Peff=1.57 MuB/Co indicates an itinerant ferromagnetic state of the Co sublattice. The third magnetic transition at TN1=5 K is observed clearly in the specific-heat study only. Both magnetic and 57Fe Mossbauer studies show that substitution of small quantities of Fe for Co was unsuccessful.