title: Nuclear polarization by optical pumping in InP:Fe above liquid nitrogen temperature.
abstract: Hyperpolarized nuclear spins are observed in optically pumped iron-doped InP from 70K to 140K. (31)P NMR was carried out at 9.28T (159.8MHz) during optical excitation with circularly polarized light, using a laser diode (λ∼830nm) as a source. The enhancement of the nuclear spin polarization by optical pumping at 70K is estimated to be about 34 for those nuclei in the region of the sample absorbing light. This enhancement decreases with increasing temperature. As the direction of the enhanced nuclear spin polarization is found parallel or antiparallel to the travelling direction of the σ(+) or σ(-), the contact hyperfine interaction is dominant compared to the dipolar hyperfine interaction.
authors.affiliation: École Polytechnique Fédérale de Lausanne, Institute of Condensed Matter Physics, CH-1015 Lausanne-EPFL, Switzerland. Electronic address: dongyoung.yoon@epfl.ch.
authors.forename: Dongyoung
authors.initials: D
authors.lastname: Yoon
authors.affiliation: École Polytechnique Fédérale de Lausanne, Institute of Condensed Matter Physics, CH-1015 Lausanne-EPFL, Switzerland.
authors.forename: Murari
authors.initials: M
authors.lastname: Soundararajan
authors.affiliation: École Polytechnique Fédérale de Lausanne, Institute of Condensed Matter Physics, CH-1015 Lausanne-EPFL, Switzerland.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Ansermet
keywords: InP:Fe; Nuclear magnetic resonance; Optical pumping