Method for producing thin film and multilayer body

A multilayer body comprising:

• a substrate;
• and
• a thin film formed on the substrate,
• wherein the thin film is formed of a first oxide containing A, Ti, and O,
• where A is at least one selected from the group consisting of Ba and Sr,
• some of oxide ions contained in the first oxide have been replaced by hydride ions,
• the substrate is formed of at least one selected from the group consisting of Si, Ge, and a metal compound that is different from the first oxide, and
• the metal compound is a substance
• (a) which has a higher oxidation-reduction potential than hydride ion, or
• (b) which is doped with hydrogen by heat treatment using a reducing agent composed of a hydride.

A multilayer body comprising:

• a substrate;
• and
• a thin film formed on the substrate,
• wherein the thin film is formed of a first oxide containing A, Ti, and O,
• where A is at least one selected from the group consisting of Ba and Sr,
• some of oxide ions contained in the first oxide have been replaced by hydride ions, and
• a hydrogen content in the substrate is less than or equal to 0.05 mol %.