Magnetic anomalies in Nd6Co(1.67)Si3: Surprising first order transitions in the low-temperature isothermal magnetization

TL;DR

This study investigates complex magnetic behavior and first-order transitions in Nd6Co(1.67)Si3, revealing field-induced spin reorientation and metastability phenomena at low temperatures.

Contribution

It demonstrates the stabilization of first-order magnetic transitions induced by field cycling in Nd6Co(1.67)Si3, highlighting novel magnetic phase behavior.

Findings

Magnetic anomalies near 50 and 20 K.

Field-induced spin reorientation below 20 K.

First-order transition only after field cycling at low temperatures.

Abstract

We present the results of magnetic measurements on Nd6Co(1.67)Si3, a compound recently reported to crystallize in a hexagonal structure (space group P6_3/m) and to undergo long range magnetic ordering below 84 K. The results reveal that the magnetism of this compound is quite complex with additional magnetic anomalies near 50 and 20 K. There are qualitative changes in the isothermal magnetization behavior with the variation of temperature. Notably, there is a field-induced spin reorientation as the temperature is lowered below 20 K. A finding we stress is that this transition is discontinuous for 1.8K in the virgin curve, but the first order character appears only after a field-cycling for a narrow higher temperature range near 5 K. Thus, this compound serves as an example for the stabilisation of first-order transition induced by magnetic-field-cycling. The issues of 'Phase co-existence' and 'meta-stability' after a field-cycling at low temperatures in this compound are also addressed.