Strong longitudinal magnetic fluctuations near critical end point in UCoAl: A 59Co-NMR study

Hiroki Nohara; Hisashi Kotegawa; Hideki Tou; Tatsuma D. Matsuda; Etsuji Yamamoto; Yoshinori Haga; Zachary Fisk; Yoshichika Onuki; Dai Aoki; Jacques Flouquet

doi:10.1143/JPSJ.80.093707

Strong longitudinal magnetic fluctuations near critical end point in UCoAl: A ⁵⁹Co-NMR study

Hiroki Nohara, Hisashi Kotegawa, Hideki Tou, Tatsuma D. Matsuda, Etsuji Yamamoto, Yoshinori Haga, Zachary Fisk, Yoshichika Onuki, Dai Aoki, Jacques Flouquet

IMR - Materials Processing and Characterization Division

Research output: Contribution to journal › Article › peer-review

20 Citations (Scopus)

Abstract

We report ⁵⁹Co-NMR measurements in UCoAl where metamagnetism occurs owing to the enhancement of ferromagnetism by a magnetic field. The metamagnetic transition from a paramagnetic (PM) state to a ferromagnetic state is a first-order transition at low temperatures, but it changes to a crossover at high temperatures on crossing the critical end point (CEP) at T_cep ∼ 12 K. The contrasting behavior between the relaxation rates 1/T ₁ and 1/T₂ suggests that the longitudinal magnetic fluctuation of the U moments is strongly enhanced, especially near the CEP. A wide diffusion of the fluctuation from the CEP can be confirmed even in the PM state where the magnetic transition does not occur.

Original language	English
Article number	093707
Journal	Journal of the Physical Society of Japan
Volume	80
Issue number	9
DOIs	https://doi.org/10.1143/JPSJ.80.093707
Publication status	Published - 2011 Sept

Keywords

Critical end point
Metamagnetism
NMR
UCoAl

Access to Document

10.1143/JPSJ.80.093707

Cite this

@article{8355a8a2f17a4ca2999f895c6119dab1,

title = "Strong longitudinal magnetic fluctuations near critical end point in UCoAl: A 59Co-NMR study",

abstract = "We report 59Co-NMR measurements in UCoAl where metamagnetism occurs owing to the enhancement of ferromagnetism by a magnetic field. The metamagnetic transition from a paramagnetic (PM) state to a ferromagnetic state is a first-order transition at low temperatures, but it changes to a crossover at high temperatures on crossing the critical end point (CEP) at Tcep ∼ 12 K. The contrasting behavior between the relaxation rates 1/T 1 and 1/T2 suggests that the longitudinal magnetic fluctuation of the U moments is strongly enhanced, especially near the CEP. A wide diffusion of the fluctuation from the CEP can be confirmed even in the PM state where the magnetic transition does not occur.",

keywords = "Critical end point, Metamagnetism, NMR, UCoAl",

author = "Hiroki Nohara and Hisashi Kotegawa and Hideki Tou and Matsuda, {Tatsuma D.} and Etsuji Yamamoto and Yoshinori Haga and Zachary Fisk and Yoshichika Onuki and Dai Aoki and Jacques Flouquet",

year = "2011",

month = sep,

doi = "10.1143/JPSJ.80.093707",

language = "English",

volume = "80",

journal = "Journal of the Physical Society of Japan",

issn = "0031-9015",

publisher = "The Physical Society of Japan",

number = "9",

}

TY - JOUR

T1 - Strong longitudinal magnetic fluctuations near critical end point in UCoAl

T2 - A 59Co-NMR study

AU - Nohara, Hiroki

AU - Kotegawa, Hisashi

AU - Tou, Hideki

AU - Matsuda, Tatsuma D.

AU - Yamamoto, Etsuji

AU - Haga, Yoshinori

AU - Fisk, Zachary

AU - Onuki, Yoshichika

AU - Aoki, Dai

AU - Flouquet, Jacques

PY - 2011/9

Y1 - 2011/9

N2 - We report 59Co-NMR measurements in UCoAl where metamagnetism occurs owing to the enhancement of ferromagnetism by a magnetic field. The metamagnetic transition from a paramagnetic (PM) state to a ferromagnetic state is a first-order transition at low temperatures, but it changes to a crossover at high temperatures on crossing the critical end point (CEP) at Tcep ∼ 12 K. The contrasting behavior between the relaxation rates 1/T 1 and 1/T2 suggests that the longitudinal magnetic fluctuation of the U moments is strongly enhanced, especially near the CEP. A wide diffusion of the fluctuation from the CEP can be confirmed even in the PM state where the magnetic transition does not occur.

AB - We report 59Co-NMR measurements in UCoAl where metamagnetism occurs owing to the enhancement of ferromagnetism by a magnetic field. The metamagnetic transition from a paramagnetic (PM) state to a ferromagnetic state is a first-order transition at low temperatures, but it changes to a crossover at high temperatures on crossing the critical end point (CEP) at Tcep ∼ 12 K. The contrasting behavior between the relaxation rates 1/T 1 and 1/T2 suggests that the longitudinal magnetic fluctuation of the U moments is strongly enhanced, especially near the CEP. A wide diffusion of the fluctuation from the CEP can be confirmed even in the PM state where the magnetic transition does not occur.

KW - Critical end point

KW - Metamagnetism

KW - NMR

KW - UCoAl

UR - http://www.scopus.com/inward/record.url?scp=80052396074&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80052396074&partnerID=8YFLogxK

U2 - 10.1143/JPSJ.80.093707

DO - 10.1143/JPSJ.80.093707

M3 - Article

AN - SCOPUS:80052396074

SN - 0031-9015

VL - 80

JO - Journal of the Physical Society of Japan

JF - Journal of the Physical Society of Japan

IS - 9

M1 - 093707

ER -

Strong longitudinal magnetic fluctuations near critical end point in UCoAl: A ⁵⁹Co-NMR study

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Cite this