Molecular Order in Buried Layers of TbPc₂ Single‐Molecule Magnets Detected by Torque Magnetometry

Abstract

Structural order and molecular orientation play a fundamental role in determining the physical properties of functional molecular materials used in devices such as organic field effect transistors and photovoltaic cells. [1] Similarly, for the development of new molecule-based devices like molecular spin-valves, molecular orientation needs to be deeply investigated and controlled. Some molecular magnetic materials may exhibit structural polymorphs which differ dramatically by the magnitude [2] or the sign [3] of the exchange coupling interaction. Single-Molecule Magnets are strongly sensitive to structural order [4] and a different orientation of the magnetic anisotropy can allow a different coupling with a functional substrate thus altering the magnetism of the hybrid molecular system in addition to its transport properties. [5]

Vanadyl phthalocyanines on graphene/SiC(0001): toward a hybrid architecture for molecular spin qubits

“…Initially, absorption spectra were recorded with linear vertical (s V ) and horizontal (s H ) polarization of the incoming X-rays to obtain the X-ray natural linear dichroism (XNLD) signal (s V -s H ), which provides information about molecular ordering on surfaces. 31,32 The XNLD spectrum (ESI, † Fig. S1.4) showed a strong dichroic signal at the L 2,3 edges of V, thereby confirming the high ordering of the molecular layer in agreement with STM results.…”

“…The dropcast contains a large number of molecules (see Methods) and could, therefore, be used as a ''fingerprint'' of the VOPc molecules at the L 2,3 edges of V. The shape of the XMCD line of the VOPc monolayer on graphene is in good agreement with the dropcast one, except for small differences attributed to the ordered configuration of the molecules deposited on graphene. 31,32 At y = 01, the %XMCD is À44% and À40% for the monolayer deposited on graphene and the dropcast, respectively. The XMCD data confirm the persistence of localized spin on the V atom after molecular adsorption on the Gr/SiC(0001) surface.…”

Magnetic Anisotropy Switch: Easy Axis to Easy Plane Conversion and Vice Versa

“…However, in the last years CTM has gained importance due to its simplicity and accuracy . A major advantage of this technique is its sensitivity, which allows for detection of the anisotropy of small crystals of microgram size or even thin layers of magnetic molecules up to room temperature . All the CTM measurements reported in this paper were obtained with the crystals mounted on the cantilever as sketched in Figure a.…”

Magnetic Anisotropy in Pentacoordinate NiII and CoII Complexes: Unraveling Electronic and Geometrical Contributions

“…Cantilever torque magnetometry (CTM) has demonstrated a major ability to separate more than one contribution to the magnetic anisotropy coming from either intramolecular or intermolecular noncollinearity. More recently, the technique was also applied to magnetic metal–organic frameworks and anisotropic thin films . The main concept of this powerful technique is to detect the magnetic torque experienced in a homogeneous field by a single crystal of a magnetic sample fixed to a cantilever acting as the upper plate of a capacitor .…”