Abstract:
High-quality single crystals of
CoTiO
3
are grown and used to elucidate in detail structural and magnetostructural effects by means of high-resolution capacitance dilatometry studies in fields up to 15 T which are complemented by specific heat and magnetization measurements. In addition, we refine the single-crystal structure of the ilmenite (
R
¯
3
) phase. At the antiferromagnetic ordering temperature
T
N
pronounced
λ
-shaped anomaly in the thermal expansion coefficients signals shrinking of both the
c
and
b
axes, indicating strong magnetoelastic coupling with uniaxial pressure along
c
yielding six times larger effect on
T
N
than pressure applied in-plane. The hydrostatic pressure dependency derived by means of Grüneisen analysis amounts to
∂
T
N
/
∂
p
≈
2.7
(
4
)
K
/
GPa
. The high-field magnetization studies in static and pulsed magnetic fields up to 60 T along with high-field thermal expansion measurements facilitate in constructing the complete anisotropic magnetic phase diagram of
CoTiO
3
. While the results confirm the presence of significant magnetodielectric coupling, our data show that magnetism drives the observed structural, dielectric, and magnetic changes both in the short-range ordered regime well above
T
N
as well as in the long-range magnetically ordered phase.