{'fraction_non_alphanumeric': 0.021450459652706845, 'fraction_numerical': 0.014300306435137897, 'mean_word_length': 4.764705882352941, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Influence of the bias sign on the dynamic modes induced by spin-transfer in exchange biased spin-valves

In this study, spin-transfer induced magnetization dynamics in exchange-biased spin-valves, for both polarities of current and field are studied. The structure of the samples included a synthetic pinned layer and a soft free layer, patterned into square pillars with a lateral size of the order of 100 nm. The resistance of the pillars was of the order of 5Omega, and the measured giant magnetoresistance reached 2.5%. The coercivity of the free layer varied between 5 and 150 Oe and a magnetostatic coupling of the same order of magnitude was measured in most cases, favoring the antiparallel state. The critical current densities were of the order of 107A/cm2. Microwave spectra obtained for negative currents and showed similar trends to those evidenced by simple Co/Cu/Co nanopillars and the small angle FMR signals can be reasonably well predicted using Kittes formula.