Influence of molybdenum substitution on the magnetic characteristics of calcium-based MOFs

In this study, a novel series of LaCaMo-based metal-organic framework (MOF) materials was synthesized and named LCM1, LCM2, LCM3 and LCM4 MOFs. The X-ray diffraction (XRD) confirmed the formation of a singlephase tetragonal scheelite-type structure with a crystalline size of 12, 30, 37 and 67 (nm). The FTIR spectra show the peaks of Mo–O at 733 and 766 (cm− 1) and a band observed at 425 and 527 (cm−1) corresponds to the absorption of Ca–O. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show
the spherical agglomerated images with increasing diameter. The selected area electron dispersive (SAED) analyses confirmed high polycrystalline phase purity. The XPS spectra validated the oxidation states of Ca2+, Mo6+,
and La3+ elements, confirming the substitution of La ions for CaMo MOF. The magnetic measurements using
vibrating sample magnetometry revealed a systematic increase in magnetization (0.002 to 0.018 emu/g) from
LCM1 to LCM4 MOFs, indicating soft ferromagnetic behavior.