Nuclear Magnetic Resonance of SuperfluidHe3nearTcin High Magnetic Fields

We present the first measurements of NMR behavior of superfluid ${\mathrm{He}}^3$ in high magnetic fields at melting pressures in the $A_1$ region in which only one spin species has undergone pairing. We observe a linear shift in the square of the transverse resonant frequency in $A_1$ with a pressure dependence of (9.52 ± 0.19)× ${10}^7$ ${\mathrm{}\left(\mathrm{Hz}\right)\mathrm{}}^2$/mbar, which is 0.188 ± 0.004 times the low-field result. This and other features that we report are in detailed agreement with the theory presented.