Epitaxial growth of Pd1−Fe films on MgO single-crystal substrate

Epitaxial growth and superconducting properties of thin-film PdFe/VN and VN/PdFe bilayers on MgO(001) substrates

“…Figure 3a,b shows the XPS spectra of the as-deposited VN/ Pd 0.92 Fe 0.08 thin film heterostructure. The binding energies of the Fe 2p 1/2 , Fe 2p 3/2 , and Pd 3d 3/2 and Pd 3d 5/2 states are 721.0, 707.7, and 340.2 and 335.0 eV, respectively, which agrees well with literature data [33,36]. Figure 3c,d shows the XPS spectra of the VN thin film on MgO.…”

“…Then, depending on the desired structure, either the Pd 1−x Fe x alloy layer or the VN layer was deposited. The Pd 1−x Fe x layers were grown by means of UHV MBE following a three-step procedure described in detail in [33]. Metallic Pd (99.95% purity, EVOCHEM GmbH, Germany) and Fe (99.97% purity, ChemPur GmbH, Germany) were co-evaporated from the pre-calibrated high-temperature effusion cells to obtain the desired Pd 1−x Fe x composition.…”

“…The in situ LEED analysis was corroborated with ex situ X-ray diffraction (XRD, BRUKER D8, Germany) measurements using Cu Kα (λ = 1.5418 Å) radiation in the Bragg-Brentano geometry with a scanning rate of 0.002°/s in the 2θ range from 17° to 82° and a step width of 0.0153°. Room-temperature XRD patterns of the pristine MgO(001) substrate, the VN thin film on MgO, Pd 0.96 Fe 0.04 on MgO and the Pd 0.96 Fe 0.04 /VN heterostructure are shown in Figure 2 The significant peak broadening of the diffraction maxima of VN and Pd 0.96 Fe 0.04 is primarily due to small coherent scattering range τ along the normal to the film plane (Scherrer broadening); XRD data with accounting for the instrument function [33]…”

“…In the resulting polycrystalline films, crystallite boundaries and crystal lattice imperfections can lead to the segregation of iron impurities and to nanoclustering of the alloy. Following the development of a way to grow single-crystalline, magnetically homogeneous epitaxial Pd 1−x Fe x films on MgO(001) single-crystalline substrates [33], we propose fully epitaxial Pd 1−x Fe x /VN and VN/Pd 1−x Fe x (x ≤ 0.08) building blocks as an alternative choice for superconducting MRAM materials, in which vanadium nitride (VN) serves as the supercon-ductor. The magnetic anisotropies of a 20 nm thick Pd 0.96 Fe 0.04 film of the first-generation epitaxial sample of VN/Pd 0.96 Fe 0.04 on MgO(001) were studied by using a ferromagnetic resonance technique in [34].…”

Обменная пружина в гетероструктуре с низкотемпературным ферромагнетиком Pd-=SUB=-0.96-=/SUB=-Fe-=SUB=-0.04-=/SUB=-

“…Сплав Pd 1−x Fe при x < 0.1 является магнитомягким низкотемпературным ферромагнетиком (ФМ) [1] и перспективен для использования в элементах сверхпроводящей спинтроники и быстрой одноквантовой логики (RSFQ -rapid single-flux quantum) [2][3][4][5][6][7]. Изменяя концентрацию железа в сплаве и условия его приготовления, можно контролировать такие ключевые параметры, как температура Кюри T C и намагниченность насыщения M s [8,9], а также варьировать величину коэрцитивного поля и магнитокристаллической анизотропии [1]. Важной составляющей для реализации спинтронных устройств на базе тонкопленочных гетероструктур является возможность закрепления заданного направления намагниченности ФМ-слоя, что обычно достигается с использованием эффекта обменного сдвига (exchange bias) на границе ФМ-и антиферромагнитного слоев [10,11].…”