Epitaxial Fe films on GaAs for hybrid semiconductor-magnetic memories

Abstract

The magnetic and structural properties of Fe films deposited by ion-beam sputtering (IBS) on (100)-oriented GaAs substrates are described. The films are between 30 and 600 nm thick and are characterized by a coercive field of approximately 3–6 Oe. The saturation magnetization and anisotropy field, inferred from vibrating sample magnetometer measurements agree substantially with the values expected for bulk Fe. Films deposited on the (100) substrate show the expected fourfold (or ‘‘biaxial’’) symmetry with no indication of a uniaxial anisotropy component. These properties make the films ideally suitable for the intended application in a hybrid semiconductor-magnetic memory, in which two magnetic remanent states with mutually orthogonal magnetization directions interact with an electronic flip-flop circuit.

High-frequency signal processing using magnetic layered structures

“…Such large fields are incompatible with devices of a limited size since substantial electromagnets as well as large power consumption are required. An alternative is to use a material with a high M s such as Fe [2][3][4]. We compare the operating frequencies of several different materials in Table 1.…”

Theory of a high frequency magnetic tunable filter and phase shifter

“…While magnetic insulators such as yttrium iron garnet ͑YIG͒ have long been used for lower frequency applications, such materials require large external magnetic fields to operate at higher frequencies. To overcome this problem, a number of publications have suggested the use of thin metallic films of Fe, [1][2][3][4] or other metallic magnets. 5 The primary reason that Fe, e.g., might be preferred over YIG is that it has a much higher saturation magnetization, M s .…”

Microwave FMR studies on ultrathin Fe/GaAs layer structures

“…The skin depth of Fe film is about 1 mm at 20 GHz, and so one might expect that the Fe film needs to be a few mm thick to reach maxima coupling. However, the skin depth of Fe film dramatically decreases at ferromagnetic resonance since the effective relative permeability becomes imaginary and its magnitude increases drastically [1,2]. As a result, significant FMR absorption level can be achieved with the Fe film of only 1400 ( A thick, as shown in Fig.…”

“…tunable microwave bandstop (notch) filters [1][2][3][4][5][6]. The increasing interest in the realization of microwave devices that utilize iron/ gallium arsenide (Fe/GaAs) layer structures is due to the fact that Fe films possess a much larger saturation magnetization than yttrium iron garnet (YIG), and also have been successfully grown on compound semiconductor substrates [7][8][9][10].…”