Robustness of Non-Fermi-Liquid Behavior near the Ferromagnetic Critical Point in Clean ZrZn₂

Abstract

Electrical resistivity ρ of a weak itinerant ferromagnet ZrZn 2 with a low residual resistivity ρ 0 ≃0.46 µΩ cm was measured under hydrostatic pressure P up to 3.2 GPa. T 2 -behavior of ρ, a hallmark of Fermi liquid, was not observed down to 1 K not only at around the ferromagnetic critical point P c ∼2 GPa but over an entire pressure range investigated. The temperature dependence of ρ at low temperatures evolved from T 5/3 in the ferromagnetic phase to T 3/2 in the paramagnetic phase. This change, however, was very weak and it was hard to capture the signature of critical point in the resistivity. Such a breakdown of Fermi liquid over a remarkably wide phase space indicates the lack of some ingredient in the description of magnetic quantum critical point in clean metals.