Spin-Lattice Coupling Across the Magnetic Quantum-Phase Transition in Copper-Containing Coordination Polymers

Area of Science:

• Materials Science
• Solid-State Physics
• Coordination Chemistry

Background:

• Spin-lattice coupling is crucial for understanding magnetic materials.
• Coordination polymers offer tunable structures for exploring fundamental physical phenomena.
• Infrared vibrational spectroscopy can probe microscopic changes in materials.

Purpose of the Study:

• To investigate the microscopic aspects of spin-lattice coupling in copper-containing coordination polymers.
• To explore how external stimuli (temperature, pressure, magnetic field) influence spin-lattice interactions.
• To correlate vibrational properties with magnetic transitions and structural characteristics.

Main Methods:

• Infrared vibrational spectroscopy was used to measure material properties.
• Two copper-containing coordination polymers, [Cu(pyz)2(2-HOpy)2](PF6)2 and [Cu(pyz)1.5(4-HOpy)2](ClO4)2, were studied.
• External stimuli including temperature, pressure, and magnetic fields were applied.

Main Results:

• Analysis of pyrazine (pyz)-related vibrational modes provided insights into magnetoelastic coupling.
• The PF6- compound showed multiple pyz distortions during the magnetic transition, while the ClO4- system exhibited a single bending mode.
• Spin-lattice coupling was maximized in the ladderlike [Cu(pyz)1.5(4-HOpy)2](ClO4)2.
• Unique high-pressure phases were observed, with potential ferroelectricity in the ClO4- compound.

Conclusions:

• Vibrational spectroscopy is a powerful tool for probing spin-lattice coupling and magnetoelastic effects.
• The structural and magnetic dimensionality significantly influences the strength of spin-lattice coupling.
• External stimuli can induce distinct phase transitions and unique material properties in coordination polymers.