Anomalous first-order transition inNd0.5Sr0.5MnO3: an interplay between kinetic arrest and thermodynamic transitions

Abstract

A detailed investigation of the first-order antiferromagnetic insulator (AFI) to ferromagnetic metal (FMM)transition in Nd0.5Sr0.5MnO3 is carried out by resistivity and magnetization measurements. These studies reveal severalanomalous features of thermomagnetic irreversibility across the first-order transition. We show thatthese anomalous features cannot be explained in terms of the supercooling effect alone and theH–T diagram basedon isothermal M–H or R–H measurements alone does not reflect the true nature of the first-order transition in thiscompound. Our investigations reveal glass-like arrest of kinetics at low temperature which playsa dominant role in the anomalous thermomagnetic irreversibility observed in this system. Theinterplay between kinetic arrest and supercooling is investigated by following novel paths in theH–T space. It is shown that coexisting FMM and AFI phases can be tuned in a numberof ways at low temperature. These measurements also show that kinetic arresttemperature and supercooling temperature are anticorrelated, i.e. regions which arearrested at low temperature have higher supercooling temperature and vice versa.