Frequency Pulling of ⁵¹V NMR in V₃O₇ at Ultralow Temperatures—Coupling of Two NMR Modes

Abstract

The temperature dependences of the two NMR frequencies of ⁵¹V in V₃O₇ (239.6 MHz and 229.8 MHz, extrapolated to 0 K) have been measured down to 30 mk at zero external field. Below 0.2 K, the ‘frequency pulling’ is observed. The temperature dependence of the shift is not the same for the two ⁵¹V NMR signals. This result is explained satisfactorily by solving the coupled equations of motion for one electron spin and two nuclear spins.