Spin-glass-like behavior in Y2Mo2O7, a concentrated, crystalline system with negligible apparent disorder

Static Critical Behavior of the Spin-Freezing Transition in the Geometrically Frustrated Pyrochlore AntiferromagnetY2Mo2Gingras1, Stager2, Raju3 et al. 1997Phys. Rev. Lett.249131842View full textAdd to dashboardCite

“…The values we obtain for γ and β are typical of those found in conventional disordered spin glasses, despite any obvious microscopic disorder in Y 2 Mo 2 O 7 [9]. High temperature measurements of the susceptibility in the Curie-Weiss regime, χ = C/(T − θ) show that θ ∼ −200K, with a Curie constant C giving an effective magnetic moment of the order of 2.5 Bohr magneton per Mo 4+ [12].…”

“…Figure 1 shows the cubic unit cell of the Mo 4+ magnetic lattice where there is a magnetic Mo moment on the vertices of the tetrahedra. The 270mg powder sample of Y 2 Mo 2 O 7 was prepared as described in Reference [9]. Neutron and X-ray powder diffraction studies show that there is no measurable amount of oxygen vacancies or intermixing between the Y 3+ and the Mo 4+ sublattices [9].…”

“…The 270mg powder sample of Y 2 Mo 2 O 7 was prepared as described in Reference [9]. Neutron and X-ray powder diffraction studies show that there is no measurable amount of oxygen vacancies or intermixing between the Y 3+ and the Mo 4+ sublattices [9]. The random disorder in that material, most likely oxygen vacancies, is therefore below the 1% detectability level.…”

“…The bulk magnetization of Y 2 Mo 2 O 7 becomes history dependent below T f ≈ 22K: the field-cooled (FC) and zero field-cooled (ZFC) magnetizations measured in a field of 100Oe show a sharp breakaway below 22K (see Fig. 1) [9].…”

Magnetothermal study of a Dy-stuffed spin ice:Dy2(DyxTi2−x)Ueland1, Lau2, Freitas3 et al. 2008Phys. Rev. B16140View full textAdd to dashboardCite

“…The energy scales of the interactions in these magnets offer unique opportunities to study how frustrated thermodynamic systems settle into their lowest energy states [1,2,3]. Examples of novel ground states observed in geometrically frustrated magnets include spin-glass-like states despite the presence of minimal structural disorder [4,5,6,7], cooperative paramagnetic states, in which the spins are locally correlated yet continue to fluctuate as T ~ 0 [8,9,10,11], and spin ice states [12,13,14,15,16,17,18,19,20,21], in which the spins freeze into a state analogous to that of the protons in frozen water. In this paper we report experimental results for variants of two spin ice materials, formed by increasing the density of spins present in the materials.…”