  Only 3% hole doping by Li is sufficient to suppress the long-range
antiferromagnetic order in La2CuO4. Spin dynamics in such a disordered state
was investigated with measurements of the dynamic magnetic structure factor
S(omega,q), using cold neutron spectroscopy, for La2(Cu0.94Li0.06)O4. The
S(omega,q) is found to sharply peak at (pi,pi), and its dynamics to be
relaxational. Confirming theoretical expectation for the quantum disordered 2D
S=1/2 Heisenberg antiferromagnet, the energy scale saturates at a finite value
at low temperatures. Possible connection to the ``pseudo spin gap'' phenomenon
observed in the NMR/NQR studies on underdoped cuprates is discussed.
