Temperature-Dependent Magnetizations and Anisotropies in Pd?Ni Multilayers

Abstract

We present Vibrating Sample Magnetometer measurements on Pd-Ni multilayers in the temperature range between 40 and 300 K. The samples were grown on mica and are fcc polycrystalline ones with a strong texture along (111). The individual Pd and Ni layer thicknesses are optimized in order to have maximum perpendicular magnetic anisotropy. We investigate the variation of the anisotropies as a function of temperature for the sample Pd 4 -Ni 2 that shows the optimum anisotropy. Strongly enhanced magnetization by 50-70% per Ni volume at low temperatures is observed. The temperature dependence of the magnetization is influenced by both, the finite thickness of the Ni layers and the thickness of the Pd layers through the variation of the interlayer coupling.Introduction Pd-based multilayers have received considerable attention since the discovery of perpendicular magnetic anisotropy (PMA) in Pd m -Co n multilayers [1] (m, n are numbers of atomic layers in the multilayer period). The most intensive research was focused on Pd-Co multilayers due to their enhanced magneto-optic response [2]. Moreover, multilayers with ultrathin Ni-layers are also of importance since they offer the possibility to bring the Curie temperature (T C ) slightly above the room temperature, which is required for technological applications. Pd-Ni multilayers were studied with focus to their structural and magneto-optic properties at room temperature [3,4]. Preliminary magnetic measurements at room temperature have revealed PMA only for n ¼ 2 [5]. Antiferromagnetic-like coupling evidence was found for n ¼ 6 [6,7]. In this work, the optimum m and n numbers for PMA are determined and the influence of the Pd thickness m on the anisotropy is examined. For the sample Pd 4 -Ni 2 , which is presenting the largest PMA, temperature-dependent anisotropies and magnetizations are discussed. Finally, we study the influence of m and n on the decrease of magnetization of Pd-Ni multilayers, as T C is approached.

Layering and temperature-dependent magnetization and anisotropy of naturally produced Ni/NiO multilayers

“…The fitting was done only up to 150 K due to decrease of T C for this sample 3. Similar influence of the magnetic layer thickness to the numerical values of the constant A has been also observed in Fe/V and Pd/Ni multilayers [27][28][29]. FIG.…”