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A single crystal, (110)-oriented dilute antiferromagnet (AF) Fe0.82Zn0.18F2 film was grown via molecular beam epitaxy on a (110)-MgF2 substrate by codepositing FeF2 and ZnF2, followed by 1.0 nm pure FeF2 and 18 nm Co layers. The exchange bias (HE) and coercivity (HC) of the Co film strongly depend on the cooling field (HCF) and temperature. For 0⩽HCF 0 for T

An electrically induced visible light emitting porous silicon (PS) device was fabricated by laterally anodizing an n‐type single‐crystal silicon (Si) wafer. Al/PS Schottky junctions exhibited rectifying I‐V characteristics with an ideality factor of 7. The intensity of current‐induced light emission increased with applied electrical current. Novel photocurrent spectra of the device under different reverse biases were measured at room temperature and reported for the first time, which showed three peaks of light absorption pertinent to the quantized energy levels of the PS. Interpretation is given based on the quantum confinement model.

The magnetization reversal in exchange biased FeF2/Co films was studied using polarized neutron reflectometry and magneto-optical imaging (MOI). After field cooling in a field H perpendicular to the c axis (the easy axis of FeF2) through the FeF2 Neel temperature, the magnetization curve measured with H parallel to the c axis showed a double loop, one with a positive exchange bias field (HE) and one with a negative HE. This behavior suggests that the antiferromagnet (AFM) is split into two types of domains with HE in opposite directions along the c axis. However, the observation of spin-flip reflectivity in the field region separating the two loops indicates that some rotation of the Co magnetization also occurred during reversal. Concurrently, small inhomogeneous domains with sizes much less than 30μm were observed using MOI. This implies that small AFM domains with opposing HE created during cooling and the resulting frustration of the interface exchange interaction with the ferromagnet are responsible ...

Atomic force and scanning tunneling microscopies were employed to investigate the surface roughness of 5.0- and 8.0‐nm-thick Co films as a function of annealing temperature. Films were epitaxially grown on (110) Al2O3 at 315°C via molecular-beam epitaxy. The as-grown films had a surface roughness average of approximately 0.7nm. Images were acquired in situ at temperatures ranging from room temperature to 600°C. For the 5.0nm films, surface roughening abruptly starts at a critical temperature T0=459°C and increases depending on the final annealing temperature and annealing time. After waiting long periods of time, so that the film is in quasiequilibrium, the roughness increases with increasing temperature T with a power-law dependence (T∕T0−1)0.5. This sudden roughening process is irreversible and possibly related to the hcp-fcc martensitic phase transition in cobalt, which occurs at 415°C in bulk, or due to bulk defect diffusion. The autocorrelation function of the images above T0 shows that the in-plane ...

The magnetic and electrical properties of ferromagentic∕superconducting∕ferromagnetic trilayers as a function of the thickness of the superconducting (SC) layer (between 5 and 15 monolayers) were measured. La2∕3Ca1∕3MnO3∕YBa2Cu3O7−δ∕La2∕3Ca1∕3MnO3 trilayered films were fabricated in situ on (001) SrTiO3 single-crystal substrates using dc sputtering with high oxygen pressures (3.5mbar). The crystalline quality of the trilayers was analyzed by x-ray diffraction. Transport and magnetic measurements revealed a weak dependence of the ferromagnet’s (FMs) Curie temperature TFMC and the FM magnetization on the thickness of the SC layer, and a strong dependence of the superconducting transition temperature TC.

The exchange bias (HE) was measured in FexZn1−xF2/Co bilayers grown on MgO (100) with and without a 1.0 nm layer of pure FeF2 at the interface between the FexZn1−xF2 and the Co layers. For x=0.83 samples with an additional 1.0 nm FeF2 interface layer HE increases by 65% when compared to the FeF2/Co bilayer. The FeF2 interface layer also causes a significant HE to appear for x