Quantum tricritical point in the temperature-pressure-magnetic field phase diagram of CeTiGe3

We report the temperature-pressure-magnetic-field phase diagram of the ferromagnetic Kondo-lattice ${\mathrm{CeTiGe}}_{3}$ determined by means of electrical resistivity measurements. Measurements up to $\ensuremath{\sim}5.8\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$ reveal a rich phase diagram with multiple phase transitions. At ambient pressure, ${\mathrm{CeTiGe}}_{3}$ orders ferromagnetically at ${T}_{\text{C}}=14$ K. Application of pressure suppresses ${T}_{\text{C}}$, but a pressure-induced ferromagnetic quantum criticality is avoided by the appearance of two new successive transitions for $p>4.1$ GPa that are probably antiferromagnetic in nature. These two transitions are suppressed under pressure, with the lower-temperature phase being fully suppressed above 5.3 GPa. The critical pressures for the presumed quantum phase transitions are ${p}_{1}\ensuremath{\cong}4.1$ GPa and ${p}_{2}\ensuremath{\cong}5.3$ GPa. Above 4.1 GPa, application of magnetic field shows a tricritical point evolving into a wing-structure phase with a quantum tricritical point at 2.8 T at 5.4 GPa, where the first-order antiferromagnetic-ferromagnetic transition changes into the second-order antiferromagnetic-ferromagnetic transition.