Temperature-field phase diagram of geometrically frustrated CePdAl

TL;DR

This study maps the complex temperature-field phase diagram of CePdAl, revealing multiple phase transitions and non-Fermi liquid behavior near critical fields, highlighting its potential for exploring exotic physics due to frustration and Kondo effects.

Contribution

It provides the first detailed phase diagram of CePdAl under varying temperature and magnetic field, uncovering multiple phase transitions and non-Fermi liquid resistivity behavior.

Findings

Multiple phase transitions occur between 3-5 T at low temperatures.

Resistivity follows a power-law with an exponent greater than 2.

Diverging electron scattering suggests proximity to a quantum critical point.

Abstract

From the electrical resistivity and ac susceptibility measurements down to $T$ = 40 mK, a rich temperature-field phase diagram has been constructed for the geometrically frustrated heavy-fermion compound CePdAl. In the limit of zero temperature, the field-induced suppression of the antiferromagnetism in this compound results in a sequence of phase transitions/corssovers, rather than a single critical point, in a critical region of field 3$-$5 T. In the lowest temperature region, a power-law description of the temperature-dependent resistivity yields $A$$\cdot$$T^n$ with $n$$>$2 for all applied fields. However, a quadratic-in-temperature resistivity term can be extracted when assuming an additional electron scattering channel from magnon-like excitations, with $A$ diverging upon approaching the critical regime. Our observations suggest CePdAl to be a new playground for exotic physics arising from the competition between Kondo screening and geometrical frustration.