Investigation of spin-polarized carrier injection effect in|YBa2Cu3O7/SrTiO3/La0.67/Sr0.33MnO3 and YBa2Cu3O7/La0.67Sr0.33MnO3 heterostructures

We report preparation and electrical properties of the YBa2Cu3O7SrTiO3(d ≈ 5.0 nm)/La0.67Sr0.33MnO3 (YBCO/STO/LSMO) and YBCO/LSMO multilayer structures grown heteroepitaxially on LaAlO3(100) substrates by single source pulsed injection MOCVD. The heterostructures were patterned in a cross-strip geometry to perform electrical measurements at T=78/300 K under magnetic field μ0H= 0/16 T using 4-probe dc method. Suppression of a supercurrent of the patterned YBCO stripes was indicated for the YBCO/LSMO heterostructure by injecting tunneling spin-polarized current fiom the underlying FM layer. The transport effects were modelled taking into account current redistribution in the adjacent conducting HTS and FM layers

Valence states of metal ions in La0.7Ce0.3MnO3La_{0.7}Ce_{0.3}MnO_{3} thin films

We report valence states of ions in $La_{0.7}Ce_{0.3}MnO_3$ thin films grown by a reactive dc magnetron sputtering. The measurements were performed by means of high-energy X-ray photoelectron spectroscopy using synchrotron radiation. It was found that Ce ion in the compound is either in tetravalent or trivalent chemical state, manganese is in divalent, trivalent and tetravalent states, while La ion existing in oxide and hydroxide chemical species is in trivalent state

Properties of hybrid MOVPE/MBE grown GaAsBi/GaAs based near-infrared emitting quantum well lasers

A combined growth approach involving both molecular-beam epitaxy and metal-organic vapor phase epitaxy has been developed to fabricate GaAsBi/GaAs-based quantum well (QW) laser structures with a Bi composition up to 8%. Lasing operation has been demonstrated at room temperature at 1.06 μm in laser diodes containing 3QWs that in turn contain approximately 6% Bi. A 5QW device demonstrated lasing at 1.09 μm at 80 K. Using temperature- and pressure-dependent measurements of stimulated emission as well as pure spontaneous emission measurements, we show that the threshold current of the devices is limited by non-radiative defect-related recombination and an inhomogeneous carrier distribution. This is suspected to be due to inhomogeneity of the QW width as well as non-uniform Bi composition in the active region

Electrically injected GaAsBi Quantum Well Lasers

GaAsBi QWs have the potential to remove inherent recombination losses thereby increasing the efficiency and reducing the temperature sensitivity of near-infrared telecommunications lasers. GaAsBi QW lasers are reported and prospects for 1550nm operation are discussed

Electrically injected GaAsBi quantum well lasers

GaAsBi QWs have the potential to remove inherent recombination losses thereby increasing the efficiency and reducing the temperature sensitivity of near-infrared telecommunications lasers. GaAsBi QW lasers are reported and prospects for 1550nm operation are discussed

Electrically injected GaAsBi quantum well lasers

GaAsBi QWs have the potential to remove inherent recombination losses thereby increasing the efficiency and reducing the temperature sensitivity of near-infrared telecommunications lasers. GaAsBi QW lasers are reported and prospects for 1550nm operation are discussed