Anomalous magnetic ordering in PrBa_2Cu_3O_{7-y} single crystals: Evidence for magnetic coupling between the Cu and Pr sublattices

TL;DR

This study investigates magnetic ordering in PrBa_2Cu_3O_{7-y} single crystals, revealing field-dependent coupling effects between Cu and Pr sublattices and identifying a field-induced phase transition.

Contribution

It provides new evidence for magnetic coupling between Cu and Pr sublattices and shows how magnetic field orientation affects magnetic ordering in these crystals.

Findings

Disappearance of the susceptibility kink after field cooling in H || ab-plane.

Persistence of the kink in the c-axis susceptibility after field cooling.

Observation of a field-induced phase transition and variable Pr^{3+} ordering temperature.

Abstract

In Al-free PrBa_2Cu_3O_{7-y} single crystals the kink in the temperature dependence of magnetic susceptibility chi_{ab}(T), connected with Pr antiferromagnetic ordering, disappears after field cooling (FC) in a field H || ab-plane. The kink in chi_c(T) remains unchanged after FC in H || c-axis. As a possible explanation, freezing of the Cu magnetic moments, lying in the ab-plane, caused by FC in H || ab, hinders their reorientation and, due to coupling between the Pr and Cu(2) sublattices, ordering of the Pr^{3+} moments. A field induced phase transition and a field dependence of the Pr^{3+} ordering temperature have been found for both H || c and H || ab.