Opto-structural and dielectric properties of 80 MeV oxygen ion irradiated natural phlogopite mica

Mechanical energy dissipation of an oscillating cantilever close to a conductive substrate partly covered with thin mica films evaluated by frequency modulation atomic force microscopy

“…The resistance value of r m is much larger than the impedance value of the capacitor of mica nanosheet as 1/(ω C m ), because tanδ is known to be about 0.2% or less for the phlogopite in the frequency range of 200-400 kHz. 44,45) Accordingly, we can approximate the current of I d as the current passing in the series circuit of C gap and C m . Namely, the current of I d is given by dC/dt × (V S -V CPD ), as appeared in Eq.…”

“…( 7) can be replaced by (R J + r m sin 2 δ) for the coverage with the mica nanosheet: It is noted that sin 2 δ becomes as small as 4 × 10 -6 , because δ for the mica is very small as tanδ ∼ 0.2%. 44,45) ORCID iDs…”

“…It is known that the dielectric energy loss of phlogopite is about 0.2% or less as tanδ in the frequency range of 200-400 kHz. 44,45) As tabulated in Table I, the values of (R J + r m sin 2 δ) for 4-, 8-, 11-, and 15-layer mica nanosheets tended to increase with their thickness, though the increase was not uniform. Assuming that each mica layer has the same value of r m and sin 2 δ is 4 × 10 -6 , the average value of r m per one layer for those samples was estimated to be 0.16 × 10 6 GΩ from the differences from the value of R J for the Ir/Si substrate.…”