Optical pumping NMR in the compensated semiconductor InP:Fe

The optical pumping NMR effect in the compensated semiconductor InP:Fe has been investigated in terms of the dependences of photon energy (E_p), helicity (sigma+-), and exposure time (tau_L) of infrared lights. The {31}P and {115}In signal enhancements show large sigma+- asymmetries and anomalous oscillations as a function of E_p. We find that (i) the oscillation period as a function of E_p is similar for {31}P and {115}In and almost field independent in spite of significant reduction of the enhancement in higher fields. (ii) A characteristic time for buildup of the {31}P polarization under the light exposure shows strong E_p-dependence, but is almost independent of sigma+-. (iii) The buildup times for {31}P and {115}In are of the same order (10^3 s), although the spin-lattice relaxation times (T_1) are different by more than three orders of magnitude between them. The results are discussed in terms of (1) discrete energy spectra due to donor-acceptor pairs (DAPs) in compensated semiconductors, and (2) interplay between {31}P and dipolar ordered indium nuclei, which are optically induced.Comment: 8 pages, 6 figures, submitted to Physical Review

Emergent Antiferromagnetism Out Of The "hidden-order" State In Uru2si2: High Magnetic Field Nuclear Magnetic Resonance To 40 T

Very high field Si29-NMR measurements using a fully Si29-enriched URu2Si2 single crystal were carried out in order to microscopically investigate the "hidden order" (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the Si29 shift, Kc29. Moreover, a strong enhancement of Kc29 develops near a critical field Hc≃35.6T, and the Si29-NMR signal disappears suddenly at Hc, indicating the total suppression of the HO state. Nevertheless, a weak and shifted Si29-NMR signal reappears for fields higher than Hc at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments. © 2014 American Physical Society.11223DMR-0654118; NSF; National Stroke FoundationMydosh, J.A., Oppeneer, P.M., (2011) Rev. Mod. Phys., 83, p. 1301. , RMPHAT 0034-6861 10.1103/RevModPhys.83.1301Okazaki, R., Shibauchi, T., Shi, H.J., Haga, Y., Matsuda, T.D., Yamamoto, E., Onuki, Y., Matsuda, Y., (2011) Science, 331, p. 439. , SCIEAS 0036-8075 10.1126/science.1197358Kambe, S., Tokunaga, Y., Sakai, H., Matsuda, T.D., Haga, Y., Fisk, Z., Walstedt, R.E., (2013) Phys. Rev. Lett., 110, p. 246406. , PRLTAO 0031-9007 10.1103/PhysRevLett.110.246406Amitsuka, H., Sato, M., Metoki, N., Yokoyama, M., Kuwahara, K., Sakakibara, T., Morimoto, H., Mydosh, J.A., (1999) Phys. Rev. Lett., 83, p. 5114. , PRLTAO 0031-9007 10.1103/PhysRevLett.83.5114Matsuda, K., Kohori, Y., Kohara, T., Kuwahara, K., Amitsuka, H., (2001) Phys. Rev. Lett., 87, p. 087203. , PRLTAO 0031-9007 10.1103/PhysRevLett.87.087203Kim, K.H., Harrison, N., Jaime, M., Boebinger, G.S., Mydosh, J.A., (2003) Phys. Rev. Lett., 91, p. 256401. , PRLTAO 0031-9007 10.1103/PhysRevLett.91.256401Kim, K.H., Harrison, N., Amitsuka, H., Jorge, G.A., Jaime, M., Mydosh, J.A., (2004) Phys. Rev. Lett., 93, p. 206402. , PRLTAO 0031-9007 10.1103/PhysRevLett.93.206402Correa, V.F., Francoual, S., Jaime, M., Harrison, N., Murphy, T.P., Palm, E.C., Tozer, S.W., Mydosh, J.A., (2012) Phys. Rev. Lett., 109, p. 246405. , PRLTAO 0031-9007 10.1103/PhysRevLett.109.246405Shishido, H., Hashimoto, K., Shibauchi, T., Sasaki, T., Oizumi, H., Kobayashi, N., Takamasu, T., Matsuda, Y., (2009) Phys. Rev. Lett., 102, p. 156403. , PRLTAO 0031-9007 10.1103/PhysRevLett.102.156403Sugiyama, K., Fuke, H., Kindo, K., Shimohata, K., Menovsky, A.A., Mydosh, J.A., Date, M., (1990) J. Phys. Soc. Jpn., 59, p. 3331. , JUPSAU 0031-9015 10.1143/JPSJ.59.3331Sugiyama, K., Nakashima, M., Ohkuni, H., Kindo, K., Haga, Y., Honma, T., Yamamoto, E., Onuki, Y., (1999) J. Phys. Soc. Jpn., 68, p. 3394. , JUPSAU 0031-9015 10.1143/JPSJ.68.3394Kohori, Y., Matsuda, K., Kohara, T., (1996) J. Phys. Soc. Jpn., 65, p. 1083. , JUPSAU 0031-9015 10.1143/JPSJ.65.1083Takagi, S., Ishihara, S., Saitoh, S., Sasaki, H., Tanida, H., Yokoyama, M., Amitsuka, H., (2007) J. Phys. Soc. Jpn., 76, p. 033708. , JUPSAU 0031-9015 10.1143/JPSJ.76.033708Altarawneh, M.M., Harrison, N., Sebastian, S.E., Balicas, L., Tobash, P.H., Thompson, J.D., Ronning, F., Bauer, E.D., (2011) Phys. Rev. Lett., 106, p. 146403. , PRLTAO 0031-9007 10.1103/PhysRevLett.106.146403Altarawneh, M.M., Harrison, N., Li, G., Balicas, L., Tobash, P.H., Ronning, F., Bauer, E.D., (2012) Phys. Rev. Lett., 108, p. 066407. , PRLTAO 0031-9007 10.1103/PhysRevLett.108.066407Oppeneer, P.M., Rusz, J., Elgazzar, S., Suzuki, M.-T., Durakiewicz, T., Mydosh, J.A., (2010) Phys. Rev. B, 82, p. 205103. , PRBMDO 1098-0121 10.1103/PhysRevB.82.205103Ikeda, H., Suzuki, M.-T., Arita, R., Takimoto, T., Shibauchi, T., Matsuda, Y., (2012) Nat. Phys., 8, p. 528. , NPAHAX 1745-2473 10.1038/nphys2330Kawasaki, Y., Ishida, K., Kitaoka, Y., Asayama, K., (1998) Phys. Rev. B, 58, p. 8634. , PRBMDO 0163-1829 10.1103/PhysRevB.58.8634Sakai, H., Tokunaga, Y., Kambe, S., Matsumoto, Y., Matsuda, T.D., Haga, Y., (2013) J. Korean Phys. Soc., 63, p. 352. , KPSJAS 0374-4884 10.3938/jkps.63.352Kawarazaki, S., Sato, M., Miyako, Y., Chigusa, N., Watanabe, K., Metoki, N., Koike, Y., Nishi, M., (2000) Phys. Rev. B, 61, p. 4167. , PRBMDO 0163-1829 10.1103/PhysRevB.61.4167Kuwahara, K., Yoshii, S., Nojiri, H., Aoki, D., Knafo, W., Duc, F., Fabrèges, X., Flouquet, J., (2013) Phys. Rev. Lett., 110, p. 216406. , PRLTAO 0031-9007 10.1103/PhysRevLett.110.216406http://link.aps.org/supplemental/10.1103/PhysRevLett.112.23640

Competition between Pauli and orbital effects in a charge-density wave system

We present angular dependent magneto-transport and magnetization measurements on alpha-(ET)2MHg(SCN)4 compounds at high magnetic fields and low temperatures. We find that the low temperature ground state undergoes two subsequent field-induced density-wave type phase transitions above a critical angle of the magnetic field with respect to the crystallographic axes. This new phase diagram may be qualitatively described assuming a charge density wave ground state which undergoes field-induced transitions due to the interplay of Pauli and orbital effects.Comment: 11 pages, 4 figures, shown at the APS march meeting 2000, appears in the Ph.D. thesis of J. S. Qualls (Florida State University, 1999), and submitted to PR

High Field Nuclear Magnetic Resonance In Transition Metal Substituted Bafe2as2

We report high field 75As nuclear magnetic resonance (NMR) measurements on Co and Cu substituted BaFe2As2 single crystals displaying same structural/magnetic transition T0?128 K. From our anisotropy studies in the paramagnetic state, we strikingly found virtually identical quadrupolar splitting and consequently the quadrupole frequency νQ?2.57(1) MHz for both compounds, despite the claim that each Cu delivers 2 extra 3d electrons in BaFe2As2 compared to Co substitution. These results allow us to conclude that a subtle change in the crystallographic structure, particularly in the Fe-As tetrahedra, must be the most probable tuning parameter to determine T0 in this class of superconductors rather than electronic doping. Furthermore, our NMR data around T0 suggest coexistence of tetragonal/paramagnetic and orthorhombic/antiferromagnetic phases between the structural and the spin density wave magnetic phase transitions, similarly to what was reported for K-doped BaFe2As2 [Urbano et al., Phys. Rev. Lett. 105, 107001 (2010)]. © 2014 AIP Publishing LLC.11517Urbano, R.R., Green, E.L., Moulton, W.G., Reyes, A.P., Kuhns, P.L., Bittar, E.M., Adriano, C., Pagliuso, P.G., (2010) Phys. Rev. Lett., 105, p. 107001. , 10.1103/PhysRevLett.105.107001Paglione, J., Greene, R.L., (2010) Nature Phys., 6, p. 645. , 10.1038/nphys1759Barzykin, V., Gor'Kov, L.P., (2009) Phys. Rev. B, 79, p. 134510. , 10.1103/PhysRevB.79.134510Granado, E., Mendonça Ferreira, L., Garcia, F., Azevedo D. G, M., Fabbris, G., Bittar, E.M., Adriano, C., Pagliuso, P.G., (2011) Phys. Rev. B, 83, p. 184508. , 10.1103/PhysRevB.83.184508Bittar, E.M., Adriano, C., Garitezi, T.M., Rosa, P.F.S., Mendonça Ferreira, L., Garcia, F., Azevedo D. G, M., Granado, E., (2011) Phys. Rev. Lett., 107, p. 267402. , 10.1103/PhysRevLett.107.267402Ideta, S., Yoshida, T., Nishi, I., Fujimori, A., Kotani, Y., Ono, K., Nakashima, Y., Arita, R., (2013) Phys. Rev. Lett., 110, p. 107007. , 10.1103/PhysRevLett.110.107007Yin, Z.P., Haule, K., Kotliar, G., (2011) Nature Mater., 10, p. 932. , 10.1038/nmat3120Rosa, P.F.S., Adriano, C., Iwamoto, W., Garitezi, T.M., Grant, T., Fisk, Z., Pagliuso, P.G., (2012) Phys. Rev. B, 86, p. 165131. , 10.1103/PhysRevB.86.165131Garitezi, T.M., Adriano, C., Rosa, P.F.S., Bittar, E.M., Bufaiçal, L., De Almeida, R.L., Granado, E., Pagliuso, P.G., (2013) Brazilian J. Phys., 43, p. 223. , 10.1007/s13538-013-0144-zRosa, P.F.S., Adriano, C., Garitezi, T.M., Grant, T., Fisk, Z., Urbano, R.R., Fernandes, E.R.R., Pagliuso, P.G., Unconventional superconductivity in substituted BaFe2As 2 revealed by pair-breaking studies Nature Scientific Reports, , (submitted)Ni, N., Thaler, A., Yan, J.Q., Kracher, A., Colombier, E., Bud'Ko, S.L., Canfield, P.C., Hannahs, S.T., (2010) Phys. Rev. B, 82, p. 024519. , 10.1103/PhysRevB.82.024519Urbano, R.R., Green, E.L., Moulton, W.G., Reyes, A.P., Kuhns, P.L., Bittar, E.M., Adriano, C., Pagliuso, P.G., (2011) J. Phys.: Conf. Ser., 273, p. 012107. , 10.1088/1742-6596/273/1/01210

Competing Orders In Underdoped (ba1-xkx)fe 2as2

We report 75As Nuclear Magnetic Resonance (NMR) measurements in the high-Tc superconductor (Ba1-xKx)Fe 2As2 in the underdoped regime. A structural transition at Ts ≃110 K is followed by an antiferromagnetic (AFM) order at TN ≃102 K for our x = 0.16 single crystal [1]. Superconductivity (SC) also appears at Tc ≃20 K. We find that the ordered Fe moment (S) is reduced upon hole-doping. Both spectrum analysis and relaxation measurements indicate that pinned vortices are present below Tc and SC is coexisting with AFM fluctuations. © Published under licence by IOP Publishing Ltd.2731Urbano R R, Green E L, Moulton W G et al 2010 arXiv:1005.3718v1 [cond-mat.supr-con]Kamihara, Y., Watanabe, T., Hirano, M., Hosono, H., (2008) J. Am. Chem. Soc., 130 (11), pp. 3296-3297Rotter, M., Tegel, M., Johrendt, D., (2008) Phys. Rev. Lett., 101 (10), p. 107006Ni, N., Tillman, M.E., Yan, J.-Q., (2008) Phys. Rev., 78 (21), p. 214515Pratt, D.K., Tian, W., Kreyssig, A., (2009) Phys. Rev. Lett., 103 (8), p. 087001Lester, C., Chu, J.-H., Analytis, J.G., (2009) Phys. Rev., 79 (14), p. 144523Johnston D C 2010 arXiv:1005.4392v1 [cond-mat.supr-con]Park, J.T., Inosov, D.S., Niedermayer, Ch., (2009) Phys. Rev. Lett., 102 (11), p. 117006Kitagawa, K., Katayama, N., Ohgushi, K., (2008) J. Phys. Soc. Jpn, 77 (11), p. 114709Julien, M.H., Mayaffre, H., Horvatic, M., (2009) Europhys. Lett., 87 (3), p. 37001Mukuda, H., Terasaki, N., Yashima, M., (2009) Physica, 469 (9-12), p. 559Fukazawa, H., Yamazaki, T., Kondo, K., (2009) J. Phys. Soc. Japan., 78 (3), p. 033704Nakai, Y., Ishida, K., Kamihara, Y., Hirano, M., Hosono, H., (2008) J. Phys. Soc. Japan., 78, p. 033704Moriya, T., (1985) Spin Fluctuations in Itinerant Electron Magnetism, , Berlin, Springer-VerlagBachman, H.N., Reyes, A.P., Mitrovic, V.F., (1998) Phys. Rev. Lett., 80 (8), p. 172

Progressive slowing down of spin fluctuations in underdoped LaFeAsO1−xF

The evolution of low-energy spin dynamics in the iron-based superconductor LaFeAsO1−xFx was studied over a broad doping, temperature, and magnetic field range (x= 0–0.15, T≤ 480 K, μ0H≤ 30 T) by means of 75As nuclear magnetic resonance. An enhanced spin-lattice relaxation rate divided by temperature (T1T)^−1 in underdoped superconducting samples (x= 0.045, 0.05, and 0.075) suggests the presence of antiferromagnetic spin fluctuations, which are strongly reduced in optimally doped (x=0.10) and completely absent in overdoped (x=0.15) samples. In contrast to previous analysis, Curie-Weiss fits are shown to be insufficient to describe the data over the whole temperature range. Instead, a Bloembergen-Purcell-Pound (BPP) model is used to describe the occurrence of a peak in (T1T)^−1 clearly above the superconducting transition, reflecting a progressive slowing down of the spin fluctuations down to the superconducting phase transition