Magnetic field resonantly enhanced free spins in underdoped YBa${}_2$Cu${}_3$O${}_{6+x}$

C. Stock, W. J. L. Buyers, K. C. Rule +4

Using neutron scattering, we investigate the effect of a magnetic field on the static and dynamic spin response in heavily underdoped superconducting YBa${}_2$Cu${}_3$O${}_{6+x}$ (YB…