Field-tuned critical fluctuations in YFe2Al10: Evidence from magnetization,27Al NMR, and NQR investigation

Abstract

We report magnetization, specific heat, and NMR investigations on YFe 2 Al 10 over a wide range in temperature and magnetic field and zero field (NQR) measurements. Magnetic susceptibility, specific heat and spin-lattice relaxation rate divided by T (1/T₁T) follow weak power law (∼T -0.4 ) temperature dependence, which is a signature of critical fluctuations of Fe moments. The value of the Sommerfeld-Wilson ratio and linear relation between 1/T₁T and χ suggest the existence of ferromagnetic correlations in this system. No magnetic ordering down to 50 mK in C p (T) and the unusual T and H scaling of the bulk and NMR data are associated with a magnetic instability which drives the system to quantum criticality. The magnetic properties of the system are tuned by field wherein ferromagnetic fluctuations are suppressed and a crossover from quantum critical to FL behavior is observed with increasing magnetic field.

Y89 NMR observation of ferromagnetic and antiferromagnetic spin fluctuations in the collapsed tetragonal phase of YFe2 (Ge,Si) Srpcic1, Jeglič2, Felner3 et al. 2017Phys. Rev. B6351View full textAdd to dashboardCite

“…Nuclear magnetic resonance (NMR) has been pivotal in studies of iron-based superconductors [20][21][22][23][24][25][26][27][28][29] as well as in studies of systems close to the quantum critical point [30][31][32][33][34][35][36][37] [39], taken at T = 300 K, shows a single line with a characteristic powder pattern of an axially symmetric shift anisotropy (Fig. 1b).…”

Contiguous3dand4fMagnetism: Strongly Correlated3dElectrons inKhuntia1, Peratheepan2, Strydom3 et al. 2014Phys. Rev. Lett.Self Cite17071View full textAdd to dashboardCite

“…Quantum criticality stemming from ferromagnetic (FM) exchange on the other hand is a rare occurrence, and has been discussed among 5f-electron systems such as UGe 2 [11,12] or UCoGe [13,14], 4f systems like YbNi 4 ðP 1−x As x Þ 2 [15,16], CeðRu 1−x Fe x ÞPO [17,18], and in weak itinerant ferromagnets like ZrZn 2 [19] and NbFe 2 [20]. YFe 2 Al 10 , an isostructural version of YbFe 2 Al 10 with no 4f electrons, is reported to be a plausible candidate for a FM quantum critical magnet [21][22][23][24].…”

Quantum critical fluctuations in layered YFe 2 Al 10

“…What type of T = 0 phase transition is responsible for the quantum criticality in YFe 2 Al 10 ? The magnitude of the uniform susceptibility and the strength of its divergence χ(T) ∼ T −1.4 , as well as the divergence of the spin lattice relaxation time 1/T 1 T from NMR measurements (25), together suggest that it involves a uniform zero wave vector q = 0 or ferromagnetic instability. YFe 2 Al 10 is a rare example of a system that forms naturally very close to a ferromagnetic QCP, without the need for tuning by pressure or composition.…”