¹⁸¹Ta (← ¹⁸¹Hf) Time-Differential Perturbed Angular Correlation Spectroscopy of Hf/Fe Multilayers

Abstract

Hf/Fe multilayers are soft magnetic materials and are a good candidate for magnetic heads of storage devices. We have investigated Hf/Fe multilayers using time-differential perturbed angular correlation (TDPAC) spectroscopy of ¹⁸¹Ta (← ¹⁸¹Hf), examining specifically the magnetic nature of the non-magnetic Hf layers sandwiched between two ferromagnetic Fe layers. We prepared multilayer samples with Hf layers of various thicknesses, [Hf(x nm)/Fe]_n (x=0.5, 1.0, 2.0, 4.8, 10.0). Three different hyperfine magnetic fields 53(1) T, 43(1) T and 2(1) T were detected in the samples of [Hf(2 nm, 4.8 nm, 10 nm)/Fe]_n. The hyperfine magnetic field of 53(1) T corresponds to Hf atoms in a turbulent interface between the Hf and Fe layers. The value of 43(1) T corresponds to Hf atoms inside Hf layers within 0.5 nm from the interface. The value of 2(1) T corresponds to Hf atoms inside the Hf layers within 3.5 nm of the interface.