J. Neu | Searcharxiv

arXiv2022

The Geometrically Frustrated Spin Glass (Fe1-pGap)2TiO5

The unusual anisotropy of the spin glass transition in the pseudobrookite system Fe$_2$TiO$_5$ has been interpreted as arising from an induced, van der Waals-like, interaction among magnetic clusters. Here we present susceptibility ($\chi$) and specific heat data (C) for Fe2TiO5 diluted with non-magnetic Ga, (Fe$_{1-p}$Ga$_p$)$_2$TiO$_5$, for disorder parameter p = 0, 0.11, and 0.42, and elastic neutron scattering data for p = 0.20. A uniform suppression of T{_g} is observed upon increasing p, along with a value of $\chi (T_g)$ that increases as T$_g$ decreases, i.e. $d\chi(T_g)/dT_g< 0$. We also observe C(T) $\propto$ T$^2$ in the low temperature limit. The observed behavior places (Fe$_{1-p}$Ga$_p$)$_2$TiO$_5$ in the category of a strongly geometrically frustrated spin glass.

cond-mat.dis-nn↗

arXiv1995

Five-loop renormalization group functions of ${O}(n)$-symmetric $ϕ^4$-theory and $\ep$-expansions of critical exponents up to $\ep^5$

Motivated by the discovery of errors in six of the 135 diagrams in the published five-loop expansions of the $β$-function and the anomalous dimensions of the ${O}(n)$-symmetric $ϕ^4$-theory in $D=4-\ep$ dimensions we present the results of a full analytic reevaluation of all diagrams. The divergences are removed by minimal subtraction and $\ep$-expansions are given for the critical exponents $η$, $ν$, and $ω$ up to order $ε^5$.

hep-th↗