Anomalous magnetoresistance and magnetocaloric properties of NdRu2Ge2

TL;DR

This study investigates the complex magnetic, magnetoresistance, and magnetocaloric behaviors of NdRu2Ge2, revealing multiple magnetic transitions, anomalous effects, and field-dependent properties in polycrystalline samples.

Contribution

It provides new insights into the magnetic and magnetocaloric properties of NdRu2Ge2, highlighting anomalous behaviors and complex magnetic states under high magnetic fields.

Findings

Multiple magnetic transitions at 10 K and 19 K.

Negative MR of about 42% near TN at 30 kOe.

Positive MR of about 35% at 3 K in 50 kOe.

Abstract

It is found that the polycrystalline NdRu2Ge2 undergoes two successive magnetic transitions at Tt=10 K and TN=19 K. Evidence of metamagnetic transition is detected in the magnetization isotherm data in the antiferromagnetic regime. Temperature dependence of magnetoresistance (MR) show that the relative magnitudes of MR at TN and Tt change considerably as the field is increased from 10 kOe to 30 kOe. Moreover, the MR is found to be positive below 9 K for 30 kOe field although the material is ferromagnetic at these temperatures. The highest value of negative MR near TN is about 42% in a field of 30 kOe, while the positive MR is about 35 % at 3 K in a field of 50 kOe. Like MR, the magnetocaloric effect at TN and Tt also shows anomalous behavior. The relative magnitudes of MCE at these temperatures are found to change with increase in field. It appears that the high field (>10 kOe) magnetic state below TN is complex, giving rise to some antiferromagnetic-like fluctuations, affecting the MR and MCE behavior.