Microscopic magnetic nature of K₂NiF₄-type 3d transition metal oxides

In order to elucidate the magnetic nature of K₂NiF₄-type 3d transition metal oxides, we have measured μ⁺SR spectra for Sr₂VO₄, LaSrVO₄, and Sr₂CrO₄ using powder samples. ZF- and wTF-μ⁺SR measurements propose that Sr₂VO₄ enters into the static antiferromagnetic (AF) order phase below 8 K. In addition, TF-μ⁺SR measurements evidence that the transition at 105 K is not magnetic but structural and/or electronic in origin. For LaSrVO₄, static long-range order has not been observed down to 20 K, while, as T decreases from 145 K, wTF asymmetry starts to decrease below 60 K, suggesting the appearance and evolution of localized magnetic moments below 60 K. For Sr₂CrO₄, by contrast, both ZF- and wTF-μ⁺SR have confirmed the presence of antiferromagnetic order below 117 K, as predicted in the χ(T) curve.