Emergent antiferromagnetism out of the "hidden-order" state in URuSi; High magnetic field nuclear magnetic resonance to 40 T

Sakai, Hironori; Urbano, R. R.*; Tokunaga, Yo; Kambe, Shinsaku; Suzuki, Michito; Kuhns, P. L.*; Reyes, A. P.*; Tobash, P. H.*; Ronning, F.*; Bauer, E. D.*; et al.

Physical Review Letters, 112(23), p.236401_1 - 236401_5, 2014/06

https://doi.org/10.1103/PhysRevLett.112.236401

Very high field Si-NMR measurements using a fully Si-enriched URuSi 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 Si shift, . Moreover, a strong enhancement of develops near a critical field T, and the Si-NMR signal disappears suddenly at , indicating the total suppression of the HO state. Nevertheless, a weak and shifted Si-NMR signal reappears for fields higher than 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.

Weak itinerant antiferromagnetism in PuIn explored using In nuclear quadrupole resonance

Chudo, Hiroyuki; Koutroulakis, G.*; Yasuoka, Hiroshi; Bauer, E. D.*; Tobash, P. H.*; Mitchell, J. N.*; Thompson, J. D.*

Journal of Physics; Condensed Matter, 26(3), p.036001_1 - 036001_5, 2014/01

https://doi.org/10.1088/0953-8984/26/3/036001

The results of In nuclear quadrupole resonance (NQR) measurements on PuIn are reported. Three of the four NQR lines of In expected for nuclear spin =9/2 are observed. The equal spacing of these lines at 20 K yields the NQR frequency of =10.45 MHz, and the asymmetry parameter of the electric field gradient, =0. The NQR line profile and the nuclear spin-lattice relaxation rate display an abrupt change at 14 K, which is associated with the onset of long-range antiferromagnetic order. The temperature dependences of the staggered magnetization , extracted from the NQR spectra, and below =14 K are well explained by the self-consistent renormalization (SCR) theory for spin fluctuations. In addition, scaling between and is also consistent with the predictions of SCR theory, providing further evidence that PuIn is a weak itinerant antiferromagnet in which spin fluctuations around the antiferromagnetic wave vector play a major role in the system's behavior at finite temperatures.

NMR/NQR Study of pressure-induced superconductor CePtIn

Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Lee, H.*; Sidorov, V. A.*; Tobash, P. H.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

Journal of Physics; Conference Series, 391, p.012057_1 - 012057_4, 2012/12

https://doi.org/10.1088/1742-6596/391/1/012057

Zero-field In-nuclear magnetic resonance (NMR) has been used to study single crystals of CePtIn, a heavy-fermion antiferromagnet with a Nel temperature () of 5.2 K at ambient pressure. The NMR spectra under zero field near the 3 line of the orthorhombic In(3) sites are tracked by temperatures down to 1.6 K and by hydrostatic pressures up to 2.4 GPa. These data reveal the coexistence of commensurate (C) and incommensurate (IC) antiferromagneic orders at ambient pressure and that the C-AFM ordering is stabilized by increasing pressures where bulk superconductivity emerges. We will show the recent data of spectra and nuclear relaxation rates () under pressures.

NQR/NMR study of antiferromagnet CePtIn using single crystals

Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Lee, H.*; Sidorov, V. A.*; Tobash, P. H.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

no journal, , 

We have performed NQR/NMR study for antiferromagnet CePtIn using single crystals. In the paramagnet state, we have observed the NQR lines for In nuclei under zero field, which have been succeeded to be assigned to the crystallographically different sites of In(1), In(2), and In(3). In the antiferromagnetically ordered state, the NQR lines become broadened and split, due to the internal fields on the respective sites. From the spectral analyses, we have found the coexistence of incommensurate and commensurate antiferromagnetic orderings and the stabilization of commensurate antiferromagnetism with applying pressure.

NMR/NQR study on the superconductivity and magnetism of Pu compounds

Yasuoka, Hiroshi; Koutroulakis, G.*; Chudo, Hiroyuki; Tobash, P. H.*; Richmond, S.*; Bauer, E. D.*; Ronning, F.*; Thompson, J. D.*; Clark, D. L.*

no journal, , 

NQR/NMR Study of antiferromagnet CePtIn using single crystals, 2

Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Lee, H.*; Sidorov, V. A.*; Tobash, P. H.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

no journal, , 

Antiferromagnet CePtIn with the Nel temperature of 5.2 K has a similar crystal structure to the well-known heavy-fermion superconductor CeCoIn and the pressure-induced superconductor CeRhIn. We have performed the NQR/NMR studies using the single crystals of CePtIn. On the basis of spectral analysis in the antiferromagnetic state, incommensurate antiferromagnetic state has been found to become stabilized well below under ambient pressure. We also have found that the commensurate antiferromagnetic state overcomes by applying pressure.