Ultrasensitive multi-mode ESR probed ferromagnetic two-level system of $M{n}^{4+}$ impurity ion in the insulated $Mn{O}_6$ complex of $SrLaAl{O}_4$ at $20mK$

Abstract

Ultrasnsitive multi-mode electron spin resonance spectroscopy in the $SrLaAl{O}_4$ dielectric resonator at $20mK$ reveals ferromagnetic states of $M{n}^{4+}$ impurity ion. The formation of ferromagnetic states in the $Mn{O}_6$ complex implies to oxygen deficiency of this multi-valence $M{n}^{4+}$ ion. Experiment results supports that an intricate electronic hybridization in $Mn{O}_6$ structural instability is related to Pseudo Jahn-Teller effect. Measured dipolar hyperfine structure parameter of nucleus is $P_{\parallel }=-3.7\times 10^{-4}c{m}^{-1}$. Mean inverse third power of the electron distance is $⟨r_q^{-3}⟩=3.325a.u.$ assuming nuclear electric quadruple moment $Q=+0.33(1)barn$. In such a state, giant g-factor is observed due to magneto (ferromagnetic) impedance taking in to account a two-level system on the adiabatic-potential-energy-surface. The spins exhibited parity is opposite in the interaction of highest-occupied-molecular-orbital and lowest-unoccupied-molecular-orbital coupling.