Critical Scaling of the Magnetization and Magnetostriction in the Weak Itinerant Ferromagnet UIr
Abstract
The weak itinerant ferromagnet UIr is studied by magnetization and magnetostriction measurements. Critical behavior, which surprisingly extends up to several Tesla, is observed at the Curie temperature TC45 K and is analyzed using Arrott and Maxwell relations. Critical exponents are found that do not match with any of the well-known universality classes. The low-temperature magnetization Ms0.5 μB const. below 3 T rises towards higher fields and converges asymptotically around 50 T with the magnetization at TC. From the magnetostriction and magnetization data, we extract the uniaxial pressure dependences of TC, using a new method presented here, and of Ms. These results should serve as a basis for understanding spin fluctuations in anisotropic itinerant ferromagnets.