  CuCrO2 offers insights into the different types of spiral magnetic orderings
that can form spontaneously due to frustration in triangular-lattice
antiferromagnets. We explore the magnetic phase diagram up to 65 T along all
the principle axes, and also use electric polarization to probe changes in the
spiral order at high magnetic fields. It is known that at zero magnetic field a
proper-screw spiral of the Cr S = 3/2 spins forms that in turn induces electric
polarization with six possible orientations ab-plane. Applied magnetic fields
in the (hard) ab-plane have been shown to induce a transition to cycloidal
spiral magnetic order above 5.3 T in those domains that have spins
perpendicular to the applied magnetic field. We show that the cycloidal order
remains unchanged all the way up to 65 T, which is one quarter of the
extrapolated saturation magnetization. On the other hand for magnetic fields
along the (easy) c-axis, we observe a transition in the electric polarization
near 45 T, and it is followed by a series of steps and/or oscillations in the
electric polarization. The data is consistent with the a
proper-screw-to-cycloidal transition that is pushed from 5.3 to 45 T by
easy-axis anisotropy, and is in turn followed by stretching of the magnetic
spiral through commensurate and incommensurate wave vectors. This work also
highlights the ability of the magnetically-induced electric polarization to
probe complex magnetic orders in regimes of phase space that are difficult to
reach with neutron diffraction.
