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Moraes FCD, Ullah S, Balanta MAG, Iikawa F, Danilov YA, Dorokhin MV, Vikhrova OV, Zvonkov BN, Hernandez FGG. Acceleration of the precession frequency for optically-oriented electron spins in ferromagnetic/semiconductor hybrids. Sci Rep 2019; 9:7294. [PMID: 31086213 PMCID: PMC6514001 DOI: 10.1038/s41598-019-43741-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 04/03/2019] [Indexed: 11/09/2022] Open
Abstract
Time-resolved Kerr rotation measurements were performed in InGaAs/GaAs quantum wells nearby a doped Mn delta layer. Our magneto-optical results show a typical time evolution of the optically-oriented electron spin in the quantum well. Surprisingly, this is strongly affected by the Mn spins, resulting in an increase of the spin precession frequency in time. This increase is attributed to the variation in the effective magnetic field induced by the dynamical relaxation of the Mn spins. Two processes are observed during electron spin precession: a quasi-instantaneous alignment of the Mn spins with photo-excited holes, followed by a slow alignment of Mn spins with the external transverse magnetic field. The first process leads to an equilibrium state imprinted in the initial precession frequency, which depends on pump power, while the second process promotes a linear frequency increase, with acceleration depending on temperature and external magnetic field. This observation yields new information about exchange process dynamics and on the possibility of constructing spin memories, which can rapidly respond to light while retaining information for a longer period.
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Affiliation(s)
- F C D Moraes
- Instituto de Física, Universidade de São Paulo, São Paulo, SP, 05508-090, Brazil.
| | - S Ullah
- Instituto de Física, Universidade de São Paulo, São Paulo, SP, 05508-090, Brazil.,Department of Physics, Gomal University, Dera Ismail Khan, 29220, KP, Pakistan
| | - M A G Balanta
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, Campinas, SP, 13083-859, Brazil
| | - F Iikawa
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, Campinas, SP, 13083-859, Brazil
| | - Y A Danilov
- Physico-Technical Research Institute, Nizhny Novgorod State University, Nizhni Novgorod, 603950, Russia
| | - M V Dorokhin
- Physico-Technical Research Institute, Nizhny Novgorod State University, Nizhni Novgorod, 603950, Russia
| | - O V Vikhrova
- Physico-Technical Research Institute, Nizhny Novgorod State University, Nizhni Novgorod, 603950, Russia
| | - B N Zvonkov
- Physico-Technical Research Institute, Nizhny Novgorod State University, Nizhni Novgorod, 603950, Russia
| | - F G G Hernandez
- Instituto de Física, Universidade de São Paulo, São Paulo, SP, 05508-090, Brazil
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