Two component butterfly hysteresis in Ru1222 ruthenocuprate

TL;DR

This study investigates the ac susceptibility butterfly hysteresis in Ru1222 ruthenocuprates, revealing two distinct magnetic contributions with different temperature and field dependencies, including a unique inverted loop feature.

Contribution

It identifies and characterizes two separate magnetic contributions to butterfly hysteresis in Ru1222, including a novel inverted loop phenomenon and their temperature and field behaviors.

Findings

Two magnetic contributions identified: ferromagnetic-like and inverted loops.

Inverted peak disappears with decreasing temperature, coercive field increases.

Saturation field at 78 K is 42 Oe with exponential field dependence.

Abstract

We report detailed studies of the ac susceptibility butterfly hysteresis on the Ru1222 ruthenocuprate compounds. Two separate contributions to these hysteresis have been identified and studied. One contribution is ferromagnetic-like and is characterized by the coercive field maximum. Another contribution, represented by the so called inverted maximum, is related to the unusual inverted loops, unique feature of Ru1222 butterfly hysteresis. The different nature of the two identified magnetic contributions is proved by the different temperature dependences involved. By lowering the temperature the inverted peak gradually disappears while the coercive field slowly raises. If the maximum dc field for the hysteresis is increased, the size of the inverted part of the butterfly hysteresis monotonously grows while the position of the peak saturates. In reaching saturation exponential field dependence has been demonstrated to take place. At T = 78 K the saturation field is 42 Oe.