たばかり

たばかり means "have just done": the action happened a short while ago, as the speaker sees it. ばかり goes after a verb's た-form, and the whole phrase then works like a noun: it takes だ or です to end the sentence and の before a noun.

How recent "just" is depends on the speaker. A month, or even a year, still counts if it feels recent.

Giving a reason or a complaint

Most sentences with たばかり go on to say what follows from it. で, なので or だから give it as a reason; なのに complains that something has already gone wrong.

ばかり is a noun here, so it takes な before のに and ので, as a noun does.

• × 買ったばかりのに → 買ったばかりなのに

たばかり or たところ

たところ is the moment straight after the action: seconds or minutes ago, often with nothing else having happened yet. たばかり is about how recent it feels, so it stretches to weeks or months, where たところ cannot.

• × 去年結婚したところです → 去年結婚したばかりです