  This work shows an unconventional route for spin-driven ferroelectricity
originating from a metastable magnetic field-induced canting of chromium
sublattice in the presence of gadolinium moments in GdCrTiO5 at low
temperatures. Compared to the isostructural neodymium compound, significant
differences of magnetism and magnetoelectric effects are seen. We present the
results of thorough investigations of temperature and magnetic field dependent
magnetization as well as ac and dc magnetic susceptibility. These bulk
measurements are complemented by local-probe spectroscopy utilizing
electron-spin resonance and muon-spin rotation/relaxation for probing the
chromium moments. Ferroelectric order is inferred from pyro- and magnetocurrent
measurements. GdCrTiO5 shows a pyrocurrent signal around 10 K, only if the
system is cooled in an applied magnetic field exceeding 10 kOe. A distinct
spin-driven ferroelectric order is revealed in this state for temperatures
below 10 K, which can be switched by changing magnetic-field direction and the
polarity of the electric field. But, the magnetic measurements reveal no clear
signature of long-range magnetic ordering. The presence of such
meta-magnetoelectric-type behaviour in the absence of any meta-magnetic
behavior is rare in the literature. Our microscopic spectroscopy results
indicate significant changes of the magnetic properties around 10 K. Probably
there is an exchange frustration between Gd and Cr moments, which prevents
long-range magnetic ordering at further high temperature. Below 10 K, weak
magnetic ordering occurs by minimizing frustration due to lattice distortion,
which helps in magnetodielectric coupling. However, the non-polar distortion
attains appreciable values after application of magnetic fields above 10 kOe to
break the spatial inversion symmetry, which creates ferroelectricity.
