title: Coherence times and Rabi oscillations in CaWO₄:Cr(5+) crystal.
abstract: The coherence times of dopant pentavalent chromium ions in CaWO₄ single crystal (0.0006at.% Cr(5+)) were investigated both theoretically and experimentally. Temperature dependences of spin-lattice relaxation time T₁ and phase memory time T(M) were measured in the temperature range 6-30 K at high (94 GHz, W band) and low (3.5 GHz, S band) frequencies of electron spin resonance. It follows from T(M) calculations that phase relaxation of Cr(5+) ion arises mainly from magnetic dipole interactions between the chromium ions. Anomalously fast damping of Rabi oscillations is detected in both S- and W-band experiments. It is shown that this phenomenon is caused by microwave field inhomogeneity inside the resonator. Relations between the damping time of Rabi oscillations, Rabi frequency and the crystal sample size are obtained. Lumped-element resonators and smaller sample dimensions are suggested to lower spin dephasing during transient nutations.
authors.affiliation: Kazan Federal University, 420008 Kazan, Russian Federation, Russia. edbaibek@gmail.com
authors.forename: Eduard
authors.initials: E
authors.lastname: Baibekov
authors.forename: Igor
authors.initials: I
authors.lastname: Kurkin
authors.forename: Marat
authors.initials: M
authors.lastname: Gafurov
authors.forename: Burkhard
authors.initials: B
authors.lastname: Endeward
authors.forename: Rafail
authors.initials: R
authors.lastname: Rakhmatullin
authors.forename: Georgy
authors.initials: G
authors.lastname: Mamin
mesh_terms: D002118:Calcium / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D003461:Crystallography; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008422:Materials Testing; D009991:Oscillometry; D010087:Oxides / Q000737:chemistry*; D014414:Tungsten / Q000737:chemistry*
chemical_list: D010087:Oxides; D002857:Chromium; C511604:tungsten oxide; D002118:Calcium; D014414:Tungsten